{"id":"CVE-2026-33173","state":"PUBLISHED","title":"Rails Active Storage has possible content type bypass via metadata in direct uploads","description":"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.","publishedAt":"2026-03-23T23:21:29.843Z","updatedAt":"2026-03-24T15:12:50.569Z","severity":{"score":5.3,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["rails activestorage"],"affected":[{"vendor":"rails","product":"activestorage","versions":[{"version":">= 8.1.0.beta1, < 8.1.2.1","status":"affected"},{"version":">= 8.0.0.beta1, < 8.0.4.1","status":"affected"},{"version":"< 7.2.3.1","status":"affected"}]}],"references":["https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg","https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53","https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e","https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0","https://github.com/rails/rails/releases/tag/v7.2.3.1","https://github.com/rails/rails/releases/tag/v8.0.4.1","https://github.com/rails/rails/releases/tag/v8.1.2.1"],"weaknesses":["CWE-925"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/33xxx/CVE-2026-33173.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33173","state":"PUBLISHED","datePublished":"2026-03-23T23:21:29.843Z","dateUpdated":"2026-03-24T15:12:50.569Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-17T22:16:36.719Z"},"containers":{"cna":{"title":"Rails Active Storage has possible content type bypass via metadata in direct uploads","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"rails","product":"activestorage","versions":[{"version":">= 8.1.0.beta1, < 8.1.2.1","status":"affected"},{"version":">= 8.0.0.beta1, < 8.0.4.1","status":"affected"},{"version":"< 7.2.3.1","status":"affected"}]}],"references":[{"url":"https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg","name":"https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53","name":"https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53","tags":["x_refsource_MISC"]},{"url":"https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e","name":"https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e","tags":["x_refsource_MISC"]},{"url":"https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0","name":"https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0","tags":["x_refsource_MISC"]},{"url":"https://github.com/rails/rails/releases/tag/v7.2.3.1","name":"https://github.com/rails/rails/releases/tag/v7.2.3.1","tags":["x_refsource_MISC"]},{"url":"https://github.com/rails/rails/releases/tag/v8.0.4.1","name":"https://github.com/rails/rails/releases/tag/v8.0.4.1","tags":["x_refsource_MISC"]},{"url":"https://github.com/rails/rails/releases/tag/v8.1.2.1","name":"https://github.com/rails/rails/releases/tag/v8.1.2.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-925","lang":"en","description":"CWE-925: Improper Verification of Intent by Broadcast Receiver","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-03-23T23:21:29.843Z"},"source":{"advisory":"GHSA-qcfx-2mfw-w4cg","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-24T14:14:22.499615Z","id":"CVE-2026-33173","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-03-24T15:12:50.569Z"}}]}}}