HAProxy HAProxy
At a glance
- Source
- NVD
- EPSS
- EPSS 0.31 % · percentile 24 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- mitre
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-130 — Improper Handling of Length Parameter Inconsistency
References
- https://www.haproxy.org
- https://www.haproxy.com/documentation/haproxy-aloha/changelog/
- https://github.com/haproxy/haproxy/commit/05a295441c621089ffa4318daf0dbca2dd756a84
- https://www.mail-archive.com/haproxy@formilux.org/msg46752.html
- https://r3verii.github.io/cve/2026/04/14/haproxy-h3-standalone-fin-smuggling.html
- https://lists.debian.org/debian-lts-announce/2026/10/msg00036.html
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 4.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N | mitre |
| CVSS 3.1 | MEDIUM 4.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N | NVD · cve@mitre.org (Secondary) |
| CVSS 3.1 | MEDIUM 5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2026-21997
- GCVE · GCVE-0-2026-33555
CERT-FR advisories
- CERTFR-2026-AVI-0486 — Multiples vulnérabilités dans les produits Microsoft · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*≥ 2.6.0 < 3.3.6
Affected products
| Product | Versions |
|---|---|
| HAProxy · HAProxy | affected 2.6 < 3.3.6 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |