{"id":"GHSA-2vqw-3mp8-cgmx","summary":"Puma PROXY Protocol v1 Accepts Repeated Protocol Headers on Persistent Connections","details":"### Impact\n\nPuma is vulnerable to source IP spoofing when `set_remote_address proxy_protocol: :v1` is enabled and persistent connections are used.\n\nPROXY protocol v1 is a connection-level protocol. [Support was added to Puma in v5.5.0](https://github.com/puma/puma/issues/2651). A proxy sends one PROXY header at the beginning of a TCP connection, before any HTTP data. Puma incorrectly re-parsed PROXY protocol headers after each keep-alive request on the same connection. An attacker able to send HTTP requests through a trusted proxy could therefore inject a second PROXY header between HTTP requests. Puma would treat the injected header as authoritative for the next request and overwrite `REMOTE_ADDR`.\n\nThis can mislead applications or middleware that use `REMOTE_ADDR` for security decisions, rate limiting, auditing, or allow/deny lists.\n\n**Only deployments that explicitly enable PROXY protocol v1 are affected**, and will have set:\n\n```ruby\nset_remote_address proxy_protocol: :v1\n```\n\nPuma's default configuration is not affected. Deployments that do not use persistent connections to Puma are also not expected to be affected by this issue.\n\n### Patches\n\nUsers should upgrade to versions 7.2.1 or 8.0.2.\n\n### Workarounds\n\nDisable PROXY protocol v1 parsing if it is not required:\n\n ```ruby\n   # remove/comment this:\n   # set_remote_address proxy_protocol: :v1\n ```\n\nUsers can also disable persistent connections to Puma, for example:\n\n```ruby\nenable_keep_alives false\n```\n\n### References\n\n- [HAProxy PROXY protocol specification](https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt)\n- [CVE-2025-31135 / GHSA-c2c3-pqw5-5p7c: go-guerrilla repeated PROXY command source IP spoofing](https://github.com/phires/go-guerrilla/security/advisories/GHSA-c2c3-pqw5-5p7c)\n- [Puma `set_remote_address` documentation](https://github.com/puma/puma/blob/master/lib/puma/dsl.rb)","aliases":["CVE-2026-47737"],"modified":"2026-07-17T21:13:37.992842824Z","published":"2026-06-09T00:09:44Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-06-09T00:09:44Z","nvd_published_at":null,"cwe_ids":["CWE-290","CWE-345"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/puma/puma/security/advisories/GHSA-2vqw-3mp8-cgmx"},{"type":"PACKAGE","url":"https://github.com/puma/puma"},{"type":"WEB","url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2026-47737.yml"},{"type":"WEB","url":"https://www.cve.org/CVERecord/SearchResults?query=CVE-2026-47737"}],"affected":[{"package":{"name":"puma","ecosystem":"RubyGems","purl":"pkg:gem/puma"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.2"}]}],"versions":["8.0.0","8.0.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-2vqw-3mp8-cgmx/GHSA-2vqw-3mp8-cgmx.json"}},{"package":{"name":"puma","ecosystem":"RubyGems","purl":"pkg:gem/puma"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"7.2.1"}]}],"versions":["5.5.0","5.5.1","5.5.2","5.6.0","5.6.1","5.6.2","5.6.4","5.6.5","5.6.6","5.6.7","5.6.8","5.6.9","6.0.0","6.0.1","6.0.2","6.1.0","6.1.1","6.2.0","6.2.1","6.2.2","6.3.0","6.3.1","6.4.0","6.4.1","6.4.2","6.4.3","6.5.0","6.6.0","6.6.1","7.0.0","7.0.0.pre1","7.0.1","7.0.2","7.0.3","7.0.4","7.1.0","7.2.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-2vqw-3mp8-cgmx/GHSA-2vqw-3mp8-cgmx.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}