← Back to CVEs

CVE-2026-33555

MEDIUM

4.0

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.

CVE Details

CVSS v3.1 Score4.0

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

Attack VectorNETWORK

ComplexityHIGH

Privileges RequiredNONE

User InteractionNONE

Published4/13/2026

Last Modified4/17/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-130

References

https://github.com/haproxy/haproxy/commit/05a295441c621089ffa4318daf0dbca2dd756a84(cve@mitre.org)

https://www.haproxy.com/documentation/haproxy-aloha/changelog/(cve@mitre.org)

https://www.haproxy.org(cve@mitre.org)

https://www.mail-archive.com/haproxy@formilux.org/msg46752.html(cve@mitre.org)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.