CVE-2025-59830

Name	CVE-2025-59830
Description	Rack is a modular Ruby web server interface. Prior to version 2.2.18, Rack::QueryParser enforces its params_limit only for parameters separated by &, while still splitting on both & and ;. As a result, attackers could use ; separators to bypass the parameter count limit and submit more parameters than intended. Applications or middleware that directly invoke Rack::QueryParser with its default configuration (no explicit delimiter) could be exposed to increased CPU and memory consumption. This can be abused as a limited denial-of-service vector. This issue has been patched in version 2.2.18.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-4357-1
Debian Bugs	1116431

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
ruby-rack (PTS)	bullseye	2.1.4-3+deb11u2	vulnerable
	bullseye (security)	2.1.4-3+deb11u4	fixed
	bookworm	2.2.13-1~deb12u1	vulnerable
	bookworm (security)	2.2.20-0+deb12u1	fixed
	trixie	3.1.16-0.1	fixed
	trixie (security)	3.1.18-1~deb13u1	fixed
	forky, sid	3.1.18-1	fixed

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

Package	Type	Release	Fixed Version	Origin	Debian Bugs
ruby-rack	source	bullseye	2.1.4-3+deb11u4	DLA-4357-1
ruby-rack	source	bookworm	2.2.20-0+deb12u1
ruby-rack	source	(unstable)	3.0.8-2		1116431

Notes

https://github.com/rack/rack/security/advisories/GHSA-625h-95r8-8xpm
Fixed by: https://github.com/rack/rack/commit/54e4ffdd5affebcb0c015cc6ae74635c0831ed71 (v2.2.18)
Rack > 3 is not affected as semicolons are not considered parameter separators in Rack 3.
Mark the first version in 3.x series entering unstable as the fixed version.