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OpenAdvisories
High ALAS2023-2026-1915 1 CVE

Important: haproxy security update (Amazon Linux 2023)

Published Jul 6, 2026 · Updated Jul 7, 2026

Ecosystem: Amazon Linux

Summary

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-55204: 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.

Fixed packages 3

ReleasePackageFixed in
Amazon Linux · 2023 haproxy 0:3.0.23-2.amzn2023.0.1
Amazon Linux · 2023 haproxy-debuginfo 0:3.0.23-2.amzn2023.0.1
Amazon Linux · 2023 haproxy-debugsource 0:3.0.23-2.amzn2023.0.1

Vulnerabilities 1

  • High 7.5
    CVE-2026-55204

    HAProxy - NULL Pointer Dereference in hpack_dht_insert Function

    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 tri…

    HAProxy HAProxy haproxy haproxy Debian Ubuntu Azure Linux Wolfi

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-55204.html