{"id":"GHSA-4q3h-vp4r-prv2","summary":"Parse Server: Account takeover via JWT algorithm confusion in Google auth adapter","details":"### Impact\n\nAn 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.\n\n### Patches\n\nThe fix 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.\n\n### Workarounds\n\nDisable Google authentication until you can upgrade.\n\n### References\n\n- GitHub advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-4q3h-vp4r-prv2\n- Fixed in Parse Server 9.3.1-alpha.4: https://github.com/parse-community/parse-server/releases/tag/9.3.1-alpha.4\n- Fixed in Parse Server 8.6.3: https://github.com/parse-community/parse-server/releases/tag/8.6.3","aliases":["BIT-parse-2026-27804","CVE-2026-27804"],"modified":"2026-03-02T12:17:22.300541Z","published":"2026-02-25T23:00:49Z","database_specific":{"severity":"CRITICAL","github_reviewed":true,"github_reviewed_at":"2026-02-25T23:00:49Z","nvd_published_at":"2026-02-26T00:16:25Z","cwe_ids":["CWE-327","CWE-345"]},"references":[{"type":"WEB","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":"WEB","url":"https://github.com/parse-community/parse-server/commit/9b94083accb7f3e72c6b8126c195c7a03dd2dfd7"},{"type":"WEB","url":"https://github.com/parse-community/parse-server/commit/9d5942d50e55c822924c27b05aa98f1393e7a330"},{"type":"PACKAGE","url":"https://github.com/parse-community/parse-server"},{"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"}],"affected":[{"package":{"name":"parse-server","ecosystem":"npm","purl":"pkg:npm/parse-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"9.0.0"},{"fixed":"9.3.1-alpha.4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-4q3h-vp4r-prv2/GHSA-4q3h-vp4r-prv2.json","last_known_affected_version_range":"\u003c= 9.3.1-alpha.3"}},{"package":{"name":"parse-server","ecosystem":"npm","purl":"pkg:npm/parse-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"8.6.3"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 8.6.2","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-4q3h-vp4r-prv2/GHSA-4q3h-vp4r-prv2.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"}]}