CVEvulnerability
CVE-2026-33555
5.8 MEDIUM
Official page ↗
- Status
- Modified
- Published
- 2026-04-13
- Last modified
- 2026-10-18
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 4.0 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
- CVSS 3.1 ([email protected])
- 5.8 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- Weaknesses
- CWE-130
Description
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.
Affected configurations
• haproxy haproxy (>= 2.6.0 < 3.3.6)
Related
Weakness · CWE (1)
- CWE-130 Improper Handling of Length Parameter Inconsistency weakness
References
- https://github.com/haproxy/haproxy/commit/05a295441c621089ffa4318daf0dbca2dd756a84 Patch
- https://r3verii.github.io/cve/2026/04/14/haproxy-h3-standalone-fin-smuggling.html Exploit, Third Party Advisory
- https://www.haproxy.com/documentation/haproxy-aloha/changelog/ Release Notes
- https://www.haproxy.org Product
- https://www.mail-archive.com/[email protected]/msg46752.html Release Notes
- https://lists.debian.org/debian-lts-announce/2026/10/msg00036.html lists.debian.org
- https://r3verii.github.io/cve/2026/04/14/haproxy-h3-standalone-fin-smuggling.html Exploit, Third Party Advisory