HTTP Request Smuggling Affecting libevent package, versions <0:2.1.13-1.el10_2


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.55% (44th percentile)

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  • Snyk IDSNYK-ALMALINUX10-LIBEVENT-19898890
  • published18 Sept 2026
  • disclosed16 Sept 2026

Introduced: 16 Sep 2026

CVE-2026-63385  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:10 libevent to version 0:2.1.13-1.el10_2 or higher.
This issue was patched in ALSA-2026:67909.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libevent package and not the libevent package as distributed by AlmaLinux. See How to fix? for AlmaLinux:10 relevant fixed versions and status.

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.

CVSS Base Scores

version 3.1