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.

PUBLISHED Reserved 2026-05-19 | Published 2026-07-14 | Updated 2026-07-14 | Assigner GitHub_M

Problem types

CWE-290: Authentication Bypass by Spoofing

CWE-345: Insufficient Verification of Data Authenticity

Product status

References

github.com/puma/puma/security/advisories/GHSA-2vqw-3mp8-cgmx

github.com/puma/puma/pull/3944

github.com/puma/puma/pull/3947

github.com/...ommit/439c6136d9c2275721b7864db3ee78af7c80889f

github.com/...ommit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58

github.com/puma/puma/releases/tag/v7.2.1

github.com/puma/puma/releases/tag/v8.0.2

cve.org (CVE-2026-47737)

nvd.nist.gov (CVE-2026-47737)

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