{"id":"GHSA-mp4x-c34x-wv3x","summary":"Feathers has an origin validation bypass via prefix matching","details":"The origin validation uses `startsWith()` for comparison, allowing attackers to bypass the check by registering a domain that shares a common prefix with an allowed origin.\n\nThe `getAllowedOrigin()` function checks if the Referer header starts with any allowed origin:\n```javascript\n// https://github.com/feathersjs/feathers/blob/dove/packages/authentication-oauth/src/strategy.ts#L75\nconst allowedOrigin = origins.find((current) =\u003e referer.toLowerCase().startsWith(current.toLowerCase()));\n```\n\nThis comparison is insufficient as it only validates the prefix. This is exploitable when the `origins` array is configured and an attacker registers a domain starting with an allowed origin string (e.g., `https://target.com.attacker.com` bypasses `https://target.com`).\n\nOn its own, tokens are still redirected to a configured origin. However, in specific scenarios an attacker can initiate the OAuth flow from an unauthorized origin and exfiltrate tokens, achieving full account takeover.\n\n**Credits**:  Abdelwahed Madani Yousfi (@vvxhid) / Edoardo Geraci (@b0-n0-b0) / Thomas Rinsma (@ThomasRinsma) From Codean Labs.","aliases":["CVE-2026-27192"],"modified":"2026-02-23T23:43:54.833394Z","published":"2026-02-19T20:32:28Z","database_specific":{"nvd_published_at":"2026-02-21T04:15:58Z","cwe_ids":["CWE-346"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-02-19T20:32:28Z"},"references":[{"type":"WEB","url":"https://github.com/feathersjs/feathers/security/advisories/GHSA-mp4x-c34x-wv3x"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27192"},{"type":"WEB","url":"https://github.com/feathersjs/feathers/commit/ee19a0ae9bc2ebf23b1fe598a1f7361981b65401"},{"type":"PACKAGE","url":"https://github.com/feathersjs/feathers"},{"type":"WEB","url":"https://github.com/feathersjs/feathers/releases/tag/v5.0.40"}],"affected":[{"package":{"name":"@feathersjs/authentication-oauth","ecosystem":"npm","purl":"pkg:npm/%40feathersjs/authentication-oauth"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.0.40"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 5.0.39","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-mp4x-c34x-wv3x/GHSA-mp4x-c34x-wv3x.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"}]}