CVE-2025-12642

NameCVE-2025-12642
Descriptionlighttpd1.4.80 incorrectly merged trailer fields into headers after http request parsing. This behavior can be exploited to conduct HTTP Header Smuggling attacks. Successful exploitation may allow an attacker to: * Bypass access control rules * Inject unsafe input into backend logic that trusts request headers * Execute HTTP Request Smuggling attacks under some conditions This issue affects lighttpd1.4.80
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
lighttpd (PTS)bullseye (security), bullseye1.4.59-1+deb11u2fixed
bookworm1.4.69-1fixed
trixie1.4.79-2fixed
forky, sid1.4.82-2fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
lighttpdsource(unstable)(not affected)

Notes

- lighttpd <not-affected> (Vulnerable code not present)
Introduced with: https://github.com/lighttpd/lighttpd1.4/commit/90002f4fd8db552b8ebe260e06c890a7f7d7e468 (lighttpd-1.4.80)
Fixed by: https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1 (lighttpd-1.4.81)

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