{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/275692?format=json","vulnerability_id":"VCID-yxp2-978j-fydw","summary":"Puma PROXY Protocol v1 Parser Allows Remote Memory Exhaustion\n## Impact\n\nPROXY protocol support for Puma was added in version 5.5.0.\n\nWhen PROXY protocol v1 support is enabled, Puma reads incoming bytes\ninto an internal buffer. It waits for \"\\r\\n\" to determine whether a\nPROXY v1 line is present. If an attacker opens a TCP connection and\ncontinuously sends bytes without CRLF, Puma keeps appending to this\npre-parse buffer.\n\nThis can cause unbounded in-process memory growth and additional\nCPU cost from repeatedly scanning the growing buffer for CRLF.\nA single, unauthenticated TCP connection can drive significant memory\ngrowth and may cause process/container OOM or degraded availability.\n\n Only Puma servers using the following non-default config are affected:\n\n set_remote_address proxy_protocol: :v1\n\n## Workarounds\n\n* Disable PROXY protocol v1 parsing if it is not required:\n  # remove/comment this:\n  # set_remote_address proxy_protocol: :v1\n\n* Restrict direct network access to Puma listeners using PROXY protocol:\n  * Only allow trusted load balancers/reverse proxies to connect.\n  * Block arbitrary client TCP access with firewall/security group rules.","aliases":[{"alias":"CVE-2026-47736"},{"alias":"GHSA-qpgp-93vx-g8v8"}],"fixed_packages":[],"affected_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/162945?format=json","purl":"pkg:gem/puma@5.5.0","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2ajy-ppmc-abd5"},{"vulnerability":"VCID-4td1-xb1a-s3fp"},{"vulnerability":"VCID-jqd6-2kq1-y7fu"},{"vulnerability":"VCID-prw8-q89n-fkcp"},{"vulnerability":"VCID-qpmp-qmsu-vufy"},{"vulnerability":"VCID-vhkc-87t9-tucj"},{"vulnerability":"VCID-y1y1-3d8u-yud7"},{"vulnerability":"VCID-yxp2-978j-fydw"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:gem/puma@5.5.0"},{"url":"http://public2.vulnerablecode.io/api/packages/304457?format=json","purl":"pkg:gem/puma@7.3","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2ajy-ppmc-abd5"},{"vulnerability":"VCID-yxp2-978j-fydw"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:gem/puma@7.3"}],"references":[{"reference_url":"https://www.cve.org/CVERecord?id=CVE-2026-47736","reference_id":"","reference_type":"","scores":[{"value":"7.5","scoring_system":"cvssv3","scoring_elements":""}],"url":"https://www.cve.org/CVERecord?id=CVE-2026-47736"}],"weaknesses":[],"exploits":[],"severity_range_score":"7.5 - 7.5","exploitability":"0.5","weighted_severity":"4.5","risk_score":2.2,"resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-yxp2-978j-fydw"}