UBUNTU-CVE-2026-34941

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Source
https://ubuntu.com/security/CVE-2026-34941
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34941.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-34941
Upstream
Published
2026-04-09T19:16:00Z
Modified
2026-05-20T16:12:55.116915888Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
  • 8.1 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a vulnerability where when transcoding a UTF-16 string to the latin1+utf16 component-model encoding it would incorrectly validate the byte length of the input string when performing a bounds check. Specifically the number of code units were checked instead of the byte length, which is twice the size of the code units. This vulnerability can cause the host to read beyond the end of a WebAssembly's linear memory in an attempt to transcode nonexistent bytes. In Wasmtime's default configuration this will read unmapped memory on a guard page, terminating the process with a segfault. Wasmtime can be configured, however, without guard pages which would mean that host memory beyond the end of linear memory may be read and interpreted as UTF-16. A host segfault is a denial-of-service vulnerability in Wasmtime, and possibly being able to read beyond the end of linear memory is additionally a vulnerability. Note that reading beyond the end of linear memory requires nonstandard configuration of Wasmtime, specifically with guard pages disabled. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.

References

Affected packages

Ubuntu:24.04:LTS / rust-wasmtime

Package

Name
rust-wasmtime
Purl
pkg:deb/ubuntu/rust-wasmtime?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

10.*
10.0.1+dfsg-7
15.*
15.0.1+dfsg-4
16.*
16.0.0+dfsg-2
16.0.0+dfsg-3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.103.0+16.0.0+dfsg-3",
            "binary_name": "librust-cranelift-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34941.json"

Ubuntu:25.10 / rust-wasmtime

Package

Name
rust-wasmtime
Purl
pkg:deb/ubuntu/rust-wasmtime?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

26.*
26.0.1+dfsg-3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.113.1+26.0.1+dfsg-3",
            "binary_name": "librust-cranelift-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34941.json"

Ubuntu:26.04:LTS / rust-wasmtime

Package

Name
rust-wasmtime
Purl
pkg:deb/ubuntu/rust-wasmtime?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

26.*
26.0.1+dfsg-3
26.0.1+dfsg-4
28.*
28.0.1+dfsg-3
29.*
29.0.1+dfsg-5
36.*
36.0.5+dfsg-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.123.5+36.0.5+dfsg-1",
            "binary_name": "librust-cranelift-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34941.json"