high7.5
CVE-2026-47737
Puma PROXY Protocol v1 Accepts Repeated Protocol Headers on Persistent Connections
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rubygems | puma | >= 8.0.0, < 8.0.2 | 8.0.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-2vqw-3mp8-cgmx
- https://github.com/puma/puma/security/advisories/GHSA-2vqw-3mp8-cgmx
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2026-47737.yml
- https://www.cve.org/CVERecord/SearchResults?query=CVE-2026-47737
- https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f
- https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58
- https://github.com/puma/puma/pull/3944
- https://github.com/puma/puma/pull/3947
- https://github.com/puma/puma/releases/tag/v7.2.1
- https://github.com/puma/puma/releases/tag/v8.0.2