{"id":"CVE-2026-27804","aliases":["BIT-parse-2026-27804","GHSA-4q3h-vp4r-prv2"],"url":"https://o3.security/vulnerability/CVE-2026-27804","summary":"Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter","details":"Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.3 and 9.1.1-alpha.4, an unauthenticated attacker can forge a Google authentication token with `alg: \"none\"` to log in as any user linked to a Google account, without knowing their credentials. All deployments with Google authentication enabled are affected. The fix in versions 8.6.3 and 9.1.1-alpha.4 hardcodes the expected `RS256` algorithm instead of trusting the JWT header, and replaces the Google adapter's custom key fetcher with `jwks-rsa` which rejects unknown key IDs. As a workaround, dsable Google authentication until upgrading is possible.","published":"2026-02-25T23:48:20.858Z","modified":"2026-08-12T03:51:18.040177712Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"parse-server","fixedVersion":"9.3.1-alpha.4"},{"ecosystem":"npm","name":"parse-server","fixedVersion":"8.6.3"}],"fix":{"url":"https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7","label":"parse-community/parse-server@9b94083"},"references":[{"type":"WEB","url":"https://github.com/parse-community/parse-server/releases/tag/8.6.3"},{"type":"WEB","url":"https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27804.json"},{"type":"ADVISORY","url":"https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27804"},{"type":"FIX","url":"https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7"},{"type":"FIX","url":"https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:18.040177712Z"}}