Inconsistent interpretation of HTTP requests in undici - CVE-2026-16728
Published: July 29, 2026
Vulnerability identifier: #VU140034
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-16728
CWE-ID: CWE-444
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Affected software:
undici
undici
Detailed vulnerability description
The vulnerability allows a remote attacker to cause downstream response desynchronization, connection hangs, or response corruption.
The vulnerability exists due to inconsistent interpretation of HTTP response framing in interceptors.retry() when retrying or resuming a partial upstream response. A remote attacker can send a partial response with mismatched framing headers to cause downstream response desynchronization, connection hangs, or response corruption.
The issue requires interceptors.retry() to be enabled and a downstream forwarder that forwards upstream headers and bodies without removing or recalculating Content-Length.
How to mitigate CVE-2026-16728
Install security update from vendor's website.