CVE-2026-58055
Publication date 28 June 2026
Last updated 2 July 2026
Ubuntu priority
Description
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| nghttp2 | 26.04 LTS resolute |
Fixed 1.68.0-2ubuntu0.2
|
| 25.10 questing |
Fixed 1.64.0-1.1ubuntu1.2
|
|
| 24.04 LTS noble |
Fixed 1.59.0-1ubuntu0.4
|
|
| 22.04 LTS jammy |
Fixed 1.43.0-1ubuntu0.4
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
Severity score breakdown
CVSS version:
Base score
6.3 · Medium
Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N
Base score
5.4 · Medium
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
References
Related Ubuntu Security Notices (USN)
- USN-8495-1
- nghttp2 vulnerability
- 2 July 2026