CVE-2026-33555

NameCVE-2026-33555
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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
haproxy (PTS)bullseye2.2.9-2+deb11u6vulnerable
bullseye (security)2.2.9-2+deb11u7vulnerable
bookworm, bookworm (security)2.6.12-1+deb12u3vulnerable
trixie (security), trixie3.0.11-1+deb13u2vulnerable
forky, sid3.2.15-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
haproxysource(unstable)3.2.15-1

Notes

Fixed by: https://git.haproxy.org/?p=haproxy-3.2.git;a=commit;h=7ab4ae974c434e62896b3c68b7b485b9dceb7a25 (v3.2.15)
Fixed by: https://git.haproxy.org/?p=haproxy-3.0.git;a=commit;h=425b969d6ea4114f4ae260f57802c65ccafc319c (v3.0.19)
Fixed by: https://git.haproxy.org/?p=haproxy-2.6.git;a=commit;h=3d8388d089170f8544c4a43bf0575f296c885f94 (v2.6.25)

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