CVE-2026-33555

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Summary

CVECVE-2026-33555
StatePUBLISHED
Assignermitre
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-13 17:16:28 UTC
Updated2026-04-13 17:16:28 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v3.1 4 MEDIUM from [email protected]

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

EPSS: 0.000090000 probability, percentile 0.007970000 (date 2026-04-15)

Problem Types: CWE-130 | CWE-130 CWE-130 Improper Handling of Length Parameter Inconsistency

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
3.1CNADECLARED4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA HAProxy HAProxy affected 2.6 3.3.6 custom Not specified

References

ReferenceSourceLinkTags
www.haproxy.org [email protected] www.haproxy.org
www.haproxy.com/documentation/haproxy-aloha/changelog [email protected] www.haproxy.com
www.mail-archive.com/[email protected]/msg46752.html [email protected] www.mail-archive.com
github.com/haproxy/haproxy/commit/05a295441c621089ffa4318daf0dbca2dd756a84 [email protected] github.com
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