{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-3419","assignerOrgId":"ce714d77-add3-4f53-aff5-83d477b104bb","state":"PUBLISHED","assignerShortName":"openjs","dateReserved":"2026-03-01T18:56:49.613Z","datePublished":"2026-03-06T17:50:58.714Z","dateUpdated":"2026-03-09T14:55:21.011Z"},"containers":{"cna":{"providerMetadata":{"orgId":"ce714d77-add3-4f53-aff5-83d477b104bb","shortName":"openjs","dateUpdated":"2026-03-06T17:54:33.542Z"},"descriptions":[{"lang":"en","value":"Fastify incorrectly accepts malformed `Content-Type` headers containing trailing characters after the subtype token, in violation of RFC 9110 §8.3.1(https://httpwg.org/specs/rfc9110.html#field.content-type). For example, a request sent with Content-Type: application/json garbage passes validation and is processed normally, rather than being rejected with 415 Unsupported Media Type.\n\nWhen regex-based content-type parsers are in use (a documented Fastify feature), the malformed value is matched against registered parsers using the full string including the trailing garbage. This means a request with an invalid content-type may be routed to and processed by a parser it should never have reached.\n\nImpact:\nAn attacker can send requests with RFC-invalid Content-Type headers that bypass validity checks, reach content-type parser matching, and be processed by the server. Requests that should be rejected at the validation stage are instead handled as if the content-type were valid.\n\nWorkarounds:\nDeploy a WAF rule to protect against this\n\nFix:\n\nThe fix is available starting with v5.8.1.","supportingMedia":[{"type":"text/html","base64":false,"value":"Fastify incorrectly accepts malformed `Content-Type` headers containing trailing characters after the subtype token, in violation of RFC 9110 §8.3.1(https://httpwg.org/specs/rfc9110.html#field.content-type). For example, a request sent with Content-Type: application/json garbage passes validation and is processed normally, rather than being rejected with 415 Unsupported Media Type.\n\nWhen regex-based content-type parsers are in use (a documented Fastify feature), the malformed value is matched against registered parsers using the full string including the trailing garbage. This means a request with an invalid content-type may be routed to and processed by a parser it should never have reached.\n\nImpact:\nAn attacker can send requests with RFC-invalid Content-Type headers that bypass validity checks, reach content-type parser matching, and be processed by the server. Requests that should be rejected at the validation stage are instead handled as if the content-type were valid.\n\nWorkarounds:\nDeploy a WAF rule to protect against this\n\nFix:\n\nThe fix is available starting with v5.8.1."}]}],"affected":[{"vendor":"fastify","product":"fastify","defaultStatus":"unaffected","versions":[{"versionType":"semver","status":"affected","version":"5.7.2","lessThan":"5.8.1"},{"versionType":"semver","status":"unaffected","version":"5.8.1"}],"packageURL":"pkg:npm/fastify"}],"references":[{"url":"https://github.com/fastify/fastify/security/advisories/GHSA-573f-x89g-hqp9"},{"url":"https://github.com/fastify/fastify/commit/67f6c9b32cb3623d3c9470cc17ed830dd2f083d7"},{"url":"https://httpwg.org/specs/rfc9110.html#field.content-type"},{"url":"https://github.com/advisories/GHSA-573f-x89g-hqp9"},{"url":"https://cna.openjsf.org/security-advisories.html"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-3419"}],"credits":[{"lang":"en","type":"reporter","value":"Saad FELLAHI"},{"lang":"en","type":"remediation developer","value":"James Sumners"},{"lang":"en","type":"coordinator","value":"Matteo Collina"},{"lang":"en","type":"remediation reviewer","value":"Ulises Gascón"}],"title":"Fastify's Missing End Anchor in \"subtypeNameReg\" Allows Malformed Content-Types to Pass Validation","metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","baseScore":5.3,"baseSeverity":"MEDIUM"},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-185","lang":"en","description":"CWE-185: Incorrect Regular Expression","type":"CWE"}]}],"x_generator":{"engine":"cve-kit 1.0.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-09T14:55:13.971640Z","id":"CVE-2026-3419","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-03-09T14:55:21.011Z"}}]}}