CVE-2026-55204 Affecting haproxy package, versions <0:2.8.14-3.el9_8.2


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.48% (39th percentile)

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  • Snyk IDSNYK-ALMALINUX9-HAPROXY-18959600
  • published19 Aug 2026
  • disclosed17 Aug 2026

Introduced: 17 Aug 2026

CVE-2026-55204  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:9 haproxy to version 0:2.8.14-3.el9_8.2 or higher.
This issue was patched in ALSA-2026:55772.

NVD Description

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

HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.

CVSS Base Scores

version 3.1