{"id":"CVE-2025-59830","aliases":["GHSA-625h-95r8-8xpm"],"url":"https://o3.security/vulnerability/CVE-2025-59830","summary":"Rack QueryParser has an unsafe default allowing params_limit bypass via semicolon-separated parameters","details":"Rack is a modular Ruby web server interface. Prior to version 2.2.18, Rack::QueryParser enforces its params_limit only for parameters separated by &, while still splitting on both & and ;. As a result, attackers could use ; separators to bypass the parameter count limit and submit more parameters than intended. Applications or middleware that directly invoke Rack::QueryParser with its default configuration (no explicit delimiter) could be exposed to increased CPU and memory consumption. This can be abused as a limited denial-of-service vector. This issue has been patched in version 2.2.18.","published":"2025-09-25T14:37:06.967Z","modified":"2026-07-15T01:49:07.302645519Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"rack","fixedVersion":"2.2.18"}],"fix":{"url":"https://github.com/rack/rack/commit/54e4ffdd5affebcb0c015cc6ae74635c0831ed71","label":"rack/rack@54e4ffd"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/59xxx/CVE-2025-59830.json"},{"type":"ADVISORY","url":"https://github.com/rack/rack/security/advisories/GHSA-625h-95r8-8xpm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-59830"},{"type":"FIX","url":"https://github.com/rack/rack/commit/54e4ffdd5affebcb0c015cc6ae74635c0831ed71"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:07.302645519Z"}}