{"id":"CVE-2025-25200","aliases":["GHSA-593f-38f6-jp5m"],"url":"https://o3.security/vulnerability/CVE-2025-25200","summary":"Koa has Inefficient Regular Expression Complexity","details":"### Summary\nKoa uses an evil regex to parse the `X-Forwarded-Proto` and `X-Forwarded-Host` HTTP headers. This can be exploited to carry out a Denial-of-Service attack.\n\n### PoC\n\nComing soon.\n\n### Impact\nThis is a Regex Denial-of-Service attack and causes memory exhaustion. The regex should be improved and empty values should not be allowed.","published":"2025-02-12T17:59:04.615Z","modified":"2026-08-12T03:51:27.630623389Z","cvss":null,"epss":{"score":0.00825,"percentile":0.54622,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"koa","fixedVersion":"2.15.4"},{"ecosystem":"npm","name":"koa","fixedVersion":"3.0.0-alpha.3"},{"ecosystem":"npm","name":"koa","fixedVersion":"1.7.1"},{"ecosystem":"npm","name":"koa","fixedVersion":"0.21.2"}],"fix":{"url":"https://github.com/koajs/koa/commit/5054af6e31ffd451a4151a1fe144cef6e5d0d83c","label":"koajs/koa@5054af6"},"references":[{"type":"WEB","url":"https://github.com/koajs/koa/blob/master/lib/request.js#L259"},{"type":"WEB","url":"https://github.com/koajs/koa/blob/master/lib/request.js#L404"},{"type":"WEB","url":"https://github.com/koajs/koa/releases/tag/2.15.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/25xxx/CVE-2025-25200.json"},{"type":"ADVISORY","url":"https://github.com/koajs/koa/security/advisories/GHSA-593f-38f6-jp5m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-25200"},{"type":"FIX","url":"https://github.com/koajs/koa/commit/5054af6e31ffd451a4151a1fe144cef6e5d0d83c"},{"type":"FIX","url":"https://github.com/koajs/koa/commit/5f294bb1c7c8d9c61904378d250439a321bffd32"},{"type":"FIX","url":"https://github.com/koajs/koa/commit/93fe903fc966635a991bcf890cfc3427d33a1a08"},{"type":"PACKAGE","url":"https://github.com/koajs/koa"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:27.630623389Z"}}