CVE-2026-47736

Name	CVE-2026-47736
Description	Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
puma (PTS)	bullseye	4.3.8-1+deb11u2	vulnerable
	bullseye (security)	4.3.8-1+deb11u3	vulnerable
	bookworm	5.6.5-3+deb12u1	vulnerable
	trixie	6.6.0-4	vulnerable
	forky, sid	8.0.2-3	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
puma	source	(unstable)	8.0.2-1

Notes

https://github.com/puma/puma/security/advisories/GHSA-qpgp-93vx-g8v8
https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f (v8.0.2)
https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58 (v7.2.1)