Hi,

The following vulnerability was published for nghttp2.

CVE-2026-58055[0]:
| nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade
| request that also carries a Content-Length header and body onto
| reusable keep-alive backend connections, re-adding the Upgrade and
| Connection headers while passing Content-Length verbatim. A backend
| that resolves the resulting ambiguous message in the attacker's
| favor enables HTTP request/response smuggling and cross-client
| response-queue poisoning.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-58055
https://www.cve.org/CVERecord?id=CVE-2026-58055
[1] https://github.com/bikini/exploitarium/tree/main/nghttp2-nghttpx-upgrade-queue-poison-poc
[2] https://github.com/nghttp2/nghttp2/commit/ab28105c4a0197da24f8bfc414bc116055249e1e

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore