{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.23.18"
              },
              {
                "introduced": "1.0.0-M1"
              },
              {
                "fixed": "1.0.0-M42"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2ae13a74d55209b6573d5228d1aa94f0361a75d0"
            },
            {
              "fixed": "b2cb8e8591391409bb1df242b45433891251b1b1"
            },
            {
              "fixed": "3f7c022e306631b006dcb43a1d7f65c0d1966f17"
            },
            {
              "fixed": "4eec2007806aa9acfefb00ebb636ddc39a147a96"
            },
            {
              "fixed": "927b67753a78c13c4445dac9307f511f5c4878c3"
            },
            {
              "fixed": "a54bc9cd31758335c7f24e29763622fd03fcf734"
            },
            {
              "fixed": "c47d9675f87603f11b32a11d503626bdf9be5c7a"
            },
            {
              "fixed": "e871ebb1d27f50c98fd56988526ce42d0fee74d6"
            }
          ],
          "repo": "https://github.com/http4s/blaze",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-mhvj-jhpq-885v"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-444"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73494.json"
  },
  "details": "blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42.",
  "id": "CVE-2026-73494",
  "modified": "2026-09-16T03:30:17.263372313Z",
  "published": "2026-09-14T17:33:49.671Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/releases/tag/v0.23.18"
    },
    {
      "type": "WEB",
      "url": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73494.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73494"
    },
    {
      "type": "FIX",
      "url": "https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17"
    },
    {
      "type": "FIX",
      "url": "https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96"
    },
    {
      "type": "FIX",
      "url": "https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3"
    },
    {
      "type": "FIX",
      "url": "https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734"
    },
    {
      "type": "FIX",
      "url": "https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a"
    },
    {
      "type": "FIX",
      "url": "https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser"
}