HAProxy - NULL Pointer Dereference in hpack_dht_insert Function
CVE-2026-55204 is fixed in 4 products on 1 platform, first by RHSA-2026:55800, released June 18, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| haproxy · Debian 14 | 3.2.20-1 | DEBIAN-CVE-2026-55204 | Jun 29, 2026 |
| haproxy · RHEL 10 | 3.0.5-4.el10_0.3 | RHSA-2026:55800 | Jun 18, 2026 |
| haproxy · RHEL 8 | 0:1.8.27-5.el8_10.2 | RHSA-2026:55859 | Aug 19, 2026 |
| haproxy · RHEL 9 | 0:2.8.14-3.el9_8.2 | RHSA-2026:55772 | Aug 19, 2026 |
| haproxy · Ubuntu 22.04.1 LTS (jammy) | 2.4.30-0ubuntu0.22.04.2 | haproxy 2.4.30-0ubuntu0.22.04.2 | Jun 24, 2026 |
| haproxy · Ubuntu 24.04.5 LTS (noble) | 2.8.16-0ubuntu0.24.04.3 | haproxy 2.8.16-0ubuntu0.24.04.3 | Jun 24, 2026 |
| haproxy · Ubuntu 25.10 (questing) | 3.0.12-0ubuntu0.25.10.5 | haproxy 3.0.12-0ubuntu0.25.10.5 | Jun 24, 2026 |
| haproxy · Ubuntu 26.04.1 LTS (resolute) | 3.2.9-1ubuntu2.2 | haproxy 3.2.9-1ubuntu2.2 | Jun 18, 2026 |
| haproxy · almalinux 10 | 3.0.5-6.el10_2.2 | ALSA-2026:55679 | Aug 17, 2026 |
| haproxy · almalinux 8 | 1.8.27-5.el8_10.2 | ALSA-2026:55859 | Aug 17, 2026 |
| haproxy · almalinux 9 | 2.8.14-3.el9_8.2 | ALSA-2026:55772 | Aug 17, 2026 |
| haproxy · amzn 2023 | 3.0.23-2.amzn2023.0.1 | ALAS2023-2026-1915 | Jul 6, 2026 |
| haproxy · ol 10 | 0:3.0.5-6.el10_2.2 | ELSA-2026-55679 | Aug 17, 2026 |
| haproxy · ol 8 | 0:1.8.27-5.el8_10.2 | ELSA-2026-55859 | Aug 17, 2026 |
| haproxy · ol 9 | 0:2.8.14-3.el9_8.2 | ELSA-2026-55772 | Aug 17, 2026 |
| haproxy · opensuse-leap 16.0 | 3.2.21+git0.dbe43be37-160000.1.1 | OPENSUSE-SU-2026:21245-1 | Jul 7, 2026 |
| haproxy · rocky 10 | 0:3.0.5-6.el10_2.2 | RLSA-2026:55679 | Aug 18, 2026 |
| haproxy · rocky 8 | 0:1.8.27-5.el8_10.2 | RLSA-2026:55859 | Aug 18, 2026 |
| haproxy · rocky 9 | 0:2.8.14-3.el9_8.2 | RLSA-2026:55772 | Aug 18, 2026 |
| haproxy · sles 15.6 | 2.8.11+git0.01c1056a4-150600.3.15.1 | SUSE-SU-2026:2652-1 | Jun 26, 2026 |
| haproxy · sles 15.7 | 2.8.11+git0.01c1056a4-150600.3.15.1 | SUSE-SU-2026:2652-1 | Jun 26, 2026 |
| haproxy · sles 16.0 | 3.2.21+git0.dbe43be37-160000.1.1 | SUSE-SU-2026:22557-1 | Jul 7, 2026 |
| haproxy-debuginfo · amzn 2023 | 3.0.23-2.amzn2023.0.1 | ALAS2023-2026-1915 | Jul 6, 2026 |
| haproxy-debugsource · amzn 2023 | 3.0.23-2.amzn2023.0.1 | ALAS2023-2026-1915 | Jul 6, 2026 |
| vim-haproxy · Ubuntu 22.04.1 LTS (jammy) | 2.4.30-0ubuntu0.22.04.2 | vim-haproxy 2.4.30-0ubuntu0.22.04.2 | Jun 24, 2026 |
| vim-haproxy · Ubuntu 24.04.5 LTS (noble) | 2.8.16-0ubuntu0.24.04.3 | vim-haproxy 2.8.16-0ubuntu0.24.04.3 | Jun 24, 2026 |
| vim-haproxy · Ubuntu 25.10 (questing) | 3.0.12-0ubuntu0.25.10.5 | vim-haproxy 3.0.12-0ubuntu0.25.10.5 | Jun 24, 2026 |
| vim-haproxy · Ubuntu 26.04.1 LTS (resolute) | 3.2.9-1ubuntu2.2 | vim-haproxy 3.2.9-1ubuntu2.2 | Jun 18, 2026 |
Patch Radar data is free to use with attribution. Terms and how to credit it.
Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.