CVE-2026-59921

NameCVE-2026-59921
DescriptionNetty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, HttpPostRequestEncoder constructs multipart HTTP request bodies by directly concatenating user-supplied filenames and field names into Content-Disposition MIME headers without validating or sanitizing CRLF characters (\r\n). Since MIME headers are delimited by CRLF, an attacker who controls the filename can inject arbitrary MIME headers into the multipart body part. The root cause is that neither the encoder nor the FileUpload implementations' setFilename() methods, which only check for null, neutralize CRLF characters before the filename is embedded into the header. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.
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
netty (PTS)bullseye1:4.1.48-4+deb11u2vulnerable
bullseye (security)1:4.1.48-4+deb11u3vulnerable
bookworm, bookworm (security)1:4.1.48-7+deb12u2vulnerable
trixie (security), trixie1:4.1.48-10+deb13u1vulnerable
forky, sid1:4.1.48-16vulnerable

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
nettysource(unstable)(unfixed)

Notes

https://github.com/netty/netty/security/advisories/GHSA-gcjf-9mgh-3p7g

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