haproxy: An issue was discovered in HAProxy before 3.3.6
CVE-2026-33555 is fixed in 2 products on 1 platform, first by haproxy 2.8.16-0ubuntu0.24.04.2, released April 13, 2026. It is not reported as exploited. Patch Radar priority: Routine.
An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be used for request smuggling. The earliest affected version is 2.6.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| haproxy · Debian 12.15 (bookworm) | 2.6.12-1+deb12u4 | DEBIAN-CVE-2026-33555 | Apr 13, 2026 |
| haproxy · Debian 13.5 (trixie) | 3.0.11-1+deb13u3 | DEBIAN-CVE-2026-33555 | Apr 13, 2026 |
| haproxy · Debian 14 | 3.2.15-1 | DEBIAN-CVE-2026-33555 | Apr 13, 2026 |
| haproxy · Ubuntu 24.04.5 LTS (noble) | 2.8.16-0ubuntu0.24.04.2 | haproxy 2.8.16-0ubuntu0.24.04.2 | Apr 13, 2026 |
| haproxy · Ubuntu 25.10 (questing) | 3.0.12-0ubuntu0.25.10.4 | haproxy 3.0.12-0ubuntu0.25.10.4 | Apr 13, 2026 |
| haproxy · Ubuntu 26.04.1 LTS (resolute) | 3.2.9-1ubuntu2.1 | haproxy 3.2.9-1ubuntu2.1 | Apr 13, 2026 |
| haproxy · opensuse-leap 16.0 | 3.2.15+git64.0fc44b458-160000.2.1 | OPENSUSE-SU-2026:20618-1 | Apr 23, 2026 |
| haproxy · sles 15.6 | 2.8.11+git0.01c1056a4-150600.3.12.1 | SUSE-SU-2026:1568-1 | Apr 23, 2026 |
| haproxy · sles 15.7 | 2.8.11+git0.01c1056a4-150600.3.12.1 | SUSE-SU-2026:1568-1 | Apr 23, 2026 |
| vim-haproxy · Ubuntu 24.04.5 LTS (noble) | 2.8.16-0ubuntu0.24.04.2 | vim-haproxy 2.8.16-0ubuntu0.24.04.2 | Apr 13, 2026 |
| vim-haproxy · Ubuntu 25.10 (questing) | 3.0.12-0ubuntu0.25.10.4 | vim-haproxy 3.0.12-0ubuntu0.25.10.4 | Apr 13, 2026 |
| vim-haproxy · Ubuntu 26.04.1 LTS (resolute) | 3.2.9-1ubuntu2.1 | vim-haproxy 3.2.9-1ubuntu2.1 | Apr 13, 2026 |
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