{"id":"CVE-2026-33173","aliases":["GHSA-qcfx-2mfw-w4cg"],"url":"https://o3.security/vulnerability/CVE-2026-33173","summary":"Rails Active Storage has possible content type bypass via metadata in direct uploads","details":"Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `DirectUploadsController` accepts arbitrary metadata from the client and persists it on the blob. Because internal flags like `identified` and `analyzed` are stored in the same metadata hash, a direct-upload client can set these flags to skip MIME detection and analysis. This allows an attacker to upload arbitrary content while claiming a safe `content_type`, bypassing any validations that rely on Active Storage's automatic content type identification. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.","published":"2026-03-23T23:21:29.843Z","modified":"2026-08-07T11:49:52.614852273Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"activestorage","fixedVersion":"8.1.2.1"},{"ecosystem":"RubyGems","name":"activestorage","fixedVersion":"8.0.4.1"},{"ecosystem":"RubyGems","name":"activestorage","fixedVersion":"7.2.3.1"}],"fix":{"url":"https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53","label":"rails/rails@707c0f1"},"references":[{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v7.2.3.1"},{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v8.0.4.1"},{"type":"WEB","url":"https://github.com/rails/rails/releases/tag/v8.1.2.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33173.json"},{"type":"ADVISORY","url":"https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33173"},{"type":"FIX","url":"https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53"},{"type":"FIX","url":"https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e"},{"type":"FIX","url":"https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:49:52.614852273Z"}}