HTTP Request Smuggling Affecting libnghttp2 package, versions <0:1.43.0-6.el9_8.2


Severity

Recommended
0.0
medium
0
10

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.26% (18th percentile)

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  • Snyk IDSNYK-ALMALINUX9-LIBNGHTTP2-18819271
  • published15 Aug 2026
  • disclosed13 Aug 2026

Introduced: 13 Aug 2026

NewCVE-2026-58055  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:9 libnghttp2 to version 0:1.43.0-6.el9_8.2 or higher.
This issue was patched in ALSA-2026:54662.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libnghttp2 package and not the libnghttp2 package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1