OESA-2025-1835

Mozilla Thunderbird is a standalone mail and newsgroup client.

Security Fix(es):

A permission leak could have occurred from a trusted site to an untrusted site via embed or object elements. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Firefox ESR < 115.17, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10458)

An attacker could have caused a use-after-free when accessibility was enabled, leading to a potentially exploitable crash. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Firefox ESR < 115.17, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10459)

The origin of an external protocol handler prompt could have been obscured using a data: URL within an iframe. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10460)

In multipart/x-mixed-replace responses, Content-Disposition: attachment in the response header was not respected and did not force a download, which could allow XSS attacks. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10461)

Truncation of a long URL could have allowed origin spoofing in a permission prompt. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10462)

Video frames could have been leaked between origins in some situations. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Firefox ESR < 115.17, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10463)

Repeated writes to history interface attributes could have been used to cause a Denial of Service condition in the browser. This was addressed by introducing rate-limiting to this API. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10464)

A clipboard "paste" button could persist across tabs which allowed a spoofing attack. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10465)

By sending a specially crafted push message, a remote server could have hung the parent process, causing the browser to become unresponsive. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10466)

Memory safety bugs present in Firefox 131, Firefox ESR 128.3, and Thunderbird 128.3. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.(CVE-2024-10467)

Using remote content in OpenPGP encrypted messages can lead to the disclosure of plaintext. This vulnerability affects Thunderbird < 128.4.3 and Thunderbird < 132.0.1.(CVE-2024-11159)

Certain WebGL operations on Apple silicon M series devices could have lead to an out-of-bounds write and memory corruption due to a flaw in Apple's GPU driver.
This bug only affected the application on Apple M series hardware. Other platforms were unaffected. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Firefox ESR < 115.18, Thunderbird < 133, Thunderbird < 128.5, and Thunderbird < 115.18.(CVE-2024-11691)

An attacker could cause a select dropdown to be shown over another tab; this could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.(CVE-2024-11692)

The executable file warning was not presented when downloading .library-ms files.
Note: This issue only affected Windows operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.(CVE-2024-11693)

Enhanced Tracking Protection's Strict mode may have inadvertently allowed a CSP frame-src bypass and DOM-based XSS through the Google SafeFrame shim in the Web Compatibility extension. This issue could have exposed users to malicious frames masquerading as legitimate content. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Firefox ESR < 115.18, Thunderbird < 133, Thunderbird < 128.5, and Thunderbird < 115.18.(CVE-2024-11694)

A crafted URL containing Arabic script and whitespace characters could have hidden the true origin of the page, resulting in a potential spoofing attack. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.(CVE-2024-11695)

The application failed to account for exceptions thrown by the loadManifestFromFile method during add-on signature verification. This flaw, triggered by an invalid or unsupported extension manifest, could have caused runtime errors that disrupted the signature validation process. As a result, the enforcement of signature validation for unrelated add-ons may have been bypassed. Signature validation in this context is used to ensure that third-party applications on the user's computer have not tampered with the user's extensions, limiting the impact of this issue. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.(CVE-2024-11696)

When handling keypress events, an attacker may have been able to trick a user into bypassing the "Open Executable File?" confirmation dialog. This could have led to malicious code execution. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.(CVE-2024-11697)

A flaw in handling fullscreen transitions may have inadvertently caused the application to become stuck in fullscreen mode when a modal dialog was opened during the transition. This issue left users unable to exit fullscreen mode using standard actions like pressing "Esc" or accessing right-click menus, resulting in a disrupted browsing experience until the browser is restarted.
This bug only affects the application when running on macOS. Other operating systems are unaffected. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.(CVE-2024-11698)

Memory safety bugs present in Firefox 132, Firefox ESR 128.4, and Thunderbird 128.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.(CVE-2024-11699)

A double-free issue could have occurred in sec_pkcs7_decoder_start_decrypt() when handling an error path. Under specific conditions, the same symmetric key could have been freed twice, potentially leading to memory corruption. This vulnerability affects Firefox < 133, Thunderbird < 133, Firefox ESR < 128.7, and Thunderbird < 128.7.(CVE-2024-11704)

In resizeToAtLeast of SkRegion.cpp, there is a possible out of bounds write due to an integer overflow. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.(CVE-2024-43097)

matrix-js-sdk is a Matrix messaging protocol Client-Server SDK for JavaScript. matrix-js-sdk before 34.11.0 is vulnerable to client-side path traversal via crafted MXC URIs. A malicious room member can trigger clients based on the matrix-js-sdk to issue arbitrary authenticated GET requests to the client's homeserver. Fixed in matrix-js-sdk 34.11.1.(CVE-2024-50336)

An attacker could write data to the user's clipboard, bypassing the user prompt, during a certain sequence of navigational events. This vulnerability affects Firefox < 129, Firefox ESR < 128.3, and Thunderbird < 128.3.(CVE-2024-8900)

A compromised content process could have allowed for the arbitrary loading of cross-origin pages. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9392)

An attacker could, via a specially crafted multipart response, execute arbitrary JavaScript under the resource://pdf.js origin. This could allow them to access cross-origin PDF content. This access is limited to "same site" documents by the Site Isolation feature on desktop clients, but full cross-origin access is possible on Android versions. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9393)

An attacker could, via a specially crafted multipart response, execute arbitrary JavaScript under the resource://devtools origin. This could allow them to access cross-origin JSON content. This access is limited to "same site" documents by the Site Isolation feature on desktop clients, but full cross-origin access is possible on Android versions. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9394)

It is currently unknown if this issue is exploitable but a condition may arise where the structured clone of certain objects could lead to memory corruption. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9396)

A missing delay in directory upload UI could have made it possible for an attacker to trick a user into granting permission via clickjacking. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9397)

By checking the result of calls to window.open with specifically set protocol handlers, an attacker could determine if the application which implements that protocol handler is installed. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9398)

A website configured to initiate a specially crafted WebTransport session could crash the Firefox process leading to a denial of service condition. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9399)

A potential memory corruption vulnerability could be triggered if an attacker had the ability to trigger an OOM at a specific moment during JIT compilation. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9400)

Memory safety bugs present in Firefox 130, Firefox ESR 115.15, Firefox ESR 128.2, and Thunderbird 128.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Firefox ESR < 115.16, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9401)

Memory safety bugs present in Firefox 130, Firefox ESR 128.2, and Thunderbird 128.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.(CVE-2024-9402)

An attacker was able to achieve code execution in the content process by exploiting a use-after-free in Animation timelines. We have had reports of this vulnerability being exploited in the wild. This vulnerability affects Firefox < 131.0.2, Firefox ESR < 128.3.1, Firefox ESR < 115.16.1, Thunderbird < 131.0.1, Thunderbird < 128.3.1, and Thunderbird < 115.16.0.(CVE-2024-9680)

Mozilla Firefox is an open source web browser from the Mozilla Foundation in the United States. There was a security vulnerability before the Mozilla Firefox 134 version, which originated from the WebChannel API for transmitting various information across processes. Instead of checking the sending principal, it accepted the sending principal. This can lead to a privilege escalation attack.(CVE-2025-0237)

A vulnerability classified as critical has been found in Mozilla Firefox up to 133.x (Web Browser).CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.This is going to have an impact on confidentiality, integrity, and availability.Upgrading to version 134 eliminates this vulnerability.(CVE-2025-0238)

Mozilla Firefox is an open source web browser from the Mozilla Foundation in the United States. There was a security vulnerability before Mozilla Firefox 134 version that originated when using Alt-Svc, ALPN failed to properly verify the certificate if the original server redirected to an unsafe site.(CVE-2025-0239)

Mozilla Firefox is an open source web browser from the Mozilla Foundation in the United States. There was a security vulnerability before the Mozilla Firefox 134 version, which originated from the fact that parsing JavaScript modules to JSON in some cases may result in cross-region access, resulting in post-release reuse.(CVE-2025-0240)

Mozilla Firefox is an open source web browser from the Mozilla Foundation in the United States. There was a security vulnerability before Mozilla Firefox 134, which originated from the fact that when segmenting specially crafted text, segmentation can destroy memory, resulting in a crash that may be exploited.(CVE-2025-0241)

Mozilla Firefox is an open source web browser from the Mozilla Foundation in the United States. There was a security vulnerability before the Mozilla Firefox 134 version, which originated from the existence of a memory security vulnerability.(CVE-2025-0242)

A vulnerability has been found in Mozilla Thunderbird (Mail Client Software) (version unknown) and classified as critical.The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.As an impact it is known to affect confidentiality, integrity, and availability.Upgrading eliminates this vulnerability.(CVE-2025-0243)

Thunderbird displayed an incorrect sender address if the From field of an email used the invalid group name syntax that is described in CVE-2024-49040. This vulnerability affects Thunderbird < 128.7 and Thunderbird < 135.(CVE-2025-0510)

An attacker could have caused a use-after-free via crafted XSLT data, leading to a potentially exploitable crash. This vulnerability affects Firefox < 135, Firefox ESR < 115.20, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1009)

An attacker could have caused a use-after-free via the Custom Highlight API, leading to a potentially exploitable crash. This vulnerability affects Firefox < 135, Firefox ESR < 115.20, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1010)

A bug in WebAssembly code generation could have lead to a crash. It may have been possible for an attacker to leverage this to achieve code execution. This vulnerability affects Firefox < 135, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1011)

A race during concurrent delazification could have led to a use-after-free. This vulnerability affects Firefox < 135, Firefox ESR < 115.20, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1012)

A race condition could have led to private browsing tabs being opened in normal browsing windows. This could have resulted in a potential privacy leak. This vulnerability affects Firefox < 135, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1013)

Certificate length was not properly checked when added to a certificate store. In practice only trusted data was processed. This vulnerability affects Firefox < 135, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1014)

The Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If another user imported the address book, clicking on the link could result in opening a web page inside Thunderbird, and that page could execute (unprivileged) JavaScript. This vulnerability affects Thunderbird < 128.7 and Thunderbird < 135.(CVE-2025-1015)

Memory safety bugs present in Firefox 134, Thunderbird 134, Firefox ESR 115.19, Firefox ESR 128.6, Thunderbird 115.19, and Thunderbird 128.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 135, Firefox ESR < 115.20, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1016)

Memory safety bugs present in Firefox 134, Thunderbird 134, Firefox ESR 128.6, and Thunderbird 128.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 135, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.(CVE-2025-1017)

On Windows, a compromised content process could use bad StreamData sent over AudioIPC to trigger a use-after-free in the Browser process. This could have led to a sandbox escape. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1930)

It was possible to cause a use-after-free in the content process side of a WebTransport connection, leading to a potentially exploitable crash. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1931)

An inconsistent comparator in xslt/txNodeSorter could have resulted in potentially exploitable out-of-bounds access. Only affected version 122 and later. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1932)

On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1933)

It was possible to interrupt the processing of a RegExp bailout and run additional JavaScript, potentially triggering garbage collection when the engine was not expecting it. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1934)

A web page could trick a user into setting that site as the default handler for a custom URL protocol. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1935)

jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been used to hide code in a web extension disguised as something else like an image. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1936)

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 115.20, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1937)

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.(CVE-2025-1938)

When requesting an OpenPGP key from a WKD server, an incorrect padding size was used and a network observer could have learned the length of the requested email address. This vulnerability affects Thunderbird < 136 and Thunderbird < 128.8.(CVE-2025-26695)

Thunderbird's update mechanism allowed a medium-integrity user process to interfere with the SYSTEM-level updater by manipulating the file-locking behavior. By injecting code into the user-privileged process, an attacker could bypass intended access controls, allowing SYSTEM-level file operations on paths controlled by a non-privileged user and enabling privilege escalation. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.(CVE-2025-2817)

By crafting a malformed file name for an attachment in a multipart message, an attacker can trick Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new message. This vulnerability could allow attackers to disclose sensitive information from the victim's system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.(CVE-2025-2830)

JavaScript code running while transforming a document with the XSLTProcessor could lead to a use-after-free. This vulnerability affects Firefox < 137, Firefox ESR < 115.22, Firefox ESR < 128.9, Thunderbird < 137, and Thunderbird < 128.9.(CVE-2025-3028)

A crafted URL containing specific Unicode characters could have hidden the true origin of the page, resulting in a potential spoofing attack. This vulnerability affects Firefox < 137, Firefox ESR < 128.9, Thunderbird < 137, and Thunderbird < 128.9.(CVE-2025-3029)

Memory safety bugs present in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 137, Firefox ESR < 128.9, Thunderbird < 137, and Thunderbird < 128.9.(CVE-2025-3030)

Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.(CVE-2025-3522)

When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick users into downloading content from untrusted sources. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.(CVE-2025-3523)

Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats (CVE-2025-3875)

Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.(CVE-2025-3909)

It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.(CVE-2025-3932)

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.(CVE-2025-4083)

A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior due to missing null checks during attribute access. This could lead to out-of-bounds read access and potentially, memory corruption. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird < 128.10.(CVE-2025-4087)

Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird < 128.10.(CVE-2025-4091)

Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 128.10 and Thunderbird < 128.10.(CVE-2025-4093)

An attacker was able to perform an out-of-bounds read or write on a JavaScript Promise object. This vulnerability affects Firefox < 138.0.4, Firefox ESR < 128.10.1, Firefox ESR < 115.23.1, Thunderbird < 128.10.2, and Thunderbird < 138.0.2.(CVE-2025-4918)

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability affects Firefox < 138.0.4, Firefox ESR < 128.10.1, Firefox ESR < 115.23.1, Thunderbird < 128.10.2, and Thunderbird < 138.0.2.(CVE-2025-4919)

Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability affects Firefox < 139, Firefox ESR < 115.24, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.(CVE-2025-5263)

Due to insufficient escaping of the newline character in the “Copy as cURL” feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This vulnerability affects Firefox < 139, Firefox ESR < 115.24, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.(CVE-2025-5264)

Due to insufficient escaping of the ampersand character in the “Copy as cURL” feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This bug only affects Firefox for Windows. Other versions of Firefox are unaffected. This vulnerability affects Firefox < 139, Firefox ESR < 115.24, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.(CVE-2025-5265)

Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability affects Firefox < 139, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.(CVE-2025-5266)

A clickjacking vulnerability could have been used to trick a user into leaking saved payment card details to a malicious page. This vulnerability affects Firefox < 139, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.(CVE-2025-5267)

Memory safety bugs present in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 139, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.(CVE-2025-5268)

Memory safety bug present in Firefox ESR 128.10, and Thunderbird 128.10. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 128.11 and Thunderbird < 128.11.(CVE-2025-5269)

A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content. This vulnerability affects Thunderbird < 128.11.1 and Thunderbird < 139.0.2.(CVE-2025-5986)