UBUNTU-CVE-2026-18540

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Source
https://ubuntu.com/security/CVE-2026-18540
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18540.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-18540
Upstream
Published
2026-09-04T18:17:00Z
Modified
2026-09-16T14:01:37Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

undici's retry interceptor can append the body of a ranged retry response to bytes already delivered from an earlier partial response while still presenting the original response's status and headers. This happens when an upstream server delivers part of a body without a trustworthy resume checkpoint, for example a non-success response whose headers were already sent or a partial-content response with an unusable content range, then closes the connection and answers the resumed range request with more bytes. As a result the response body can be longer than the Content-Length that the application observes. An application that relays such a response to a downstream HTTP/1.1 peer without normalizing the framing can emit a body that exceeds the forwarded Content-Length, and the excess bytes can be interpreted as the start of a following response, which enables downstream response splitting or desynchronization. Exploitation requires an attacker-controlled upstream server and an application that forwards the response through a framing-sensitive path. This affects undici versions before 6.28.1, from 7.0.0 up to 7.29.1, and from 8.0.0 up to 8.10.2. Users should upgrade to undici 6.28.1, 7.29.1, or 8.10.2.

References

Affected packages

Ubuntu:24.04:LTS / node-undici

Package

Name
node-undici
Purl
pkg:deb/ubuntu/node-undici?arch=source&distro=noble

Affected ranges

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

Affected versions

5.*
5.22.1+dfsg1+~cs20.10.10.2-1ubuntu1
5.26.3+dfsg1+~cs23.10.12-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "node-llhttp",
            "binary_version": "9.1.3~5.26.3+dfsg1+~cs23.10.12-2"
        },
        {
            "binary_name": "node-undici",
            "binary_version": "5.26.3+dfsg1+~cs23.10.12-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18540.json"

Ubuntu:26.04:LTS / node-undici

Package

Name
node-undici
Purl
pkg:deb/ubuntu/node-undici?arch=source&distro=resolute

Affected ranges

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

Affected versions

7.*
7.3.0+dfsg1+~cs24.12.11-2
7.16.0+dfsg+~cs3.2.0-2
7.18.2+dfsg+~cs3.2.0-1
7.18.2+dfsg+~cs3.2.0-1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "node-undici",
            "binary_version": "7.18.2+dfsg+~cs3.2.0-1build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-18540.json"