CVE-2026-47737

Name	CVE-2026-47737
Description	Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, Puma is vulnerable to source IP spoofing when set_remote_address proxy_protocol: :v1 is enabled and persistent connections are used because Puma incorrectly re-parses PROXY protocol headers after each keep-alive request on the same connection, allowing an attacker to inject a second PROXY header and overwrite REMOTE_ADDR. 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-2vqw-3mp8-cgmx
https://github.com/puma/puma/pull/3944
https://github.com/puma/puma/pull/3947
https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f (v8.0.2)
https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58 (v7.2.1)