{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "5.7.2"
              },
              {
                "fixed": "5.8.1"
              }
            ]
          },
          "events": [
            {
              "introduced": "e1e4fe75910c36e1b9ebb87026ca16c053a9c1f2"
            },
            {
              "fixed": "073ff8132f350aaa53935231019499e983cb9794"
            },
            {
              "fixed": "67f6c9b32cb3623d3c9470cc17ed830dd2f083d7"
            }
          ],
          "repo": "https://github.com/fastify/fastify",
          "type": "GIT"
        }
      ]
    }
  ],
  "details": "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.",
  "id": "CVE-2026-3419",
  "modified": "2026-04-01T23:09:56.431433058Z",
  "published": "2026-03-06T18:16:22.213Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/fastify/fastify/security/advisories/GHSA-573f-x89g-hqp9"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-3419"
    },
    {
      "type": "FIX",
      "url": "https://github.com/advisories/GHSA-573f-x89g-hqp9"
    },
    {
      "type": "FIX",
      "url": "https://github.com/fastify/fastify/commit/67f6c9b32cb3623d3c9470cc17ed830dd2f083d7"
    },
    {
      "type": "ARTICLE",
      "url": "https://httpwg.org/specs/rfc9110.html#field.content-type"
    }
  ],
  "related": [
    "GHSA-573f-x89g-hqp9"
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}