Vulnerabilities in pkg:maven/org.http4s/blaze-http_2.12

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-46q4-43ph-c6fr",
  "modified" : "2026-08-12T21:12:00Z",
  "published" : "2026-07-24T22:26:48Z",
  "aliases" : [ "CVE-2026-73495" ],
  "summary" : "blaze: Chunked-body trailer fields promoted into Request.headers in blaze-server (front-end header-sanitization bypass)",
  "details" : "### Summary\n  blaze-server can merge HTTP/1.1 chunked-body trailer fields into `Request.headers`. Because trailer fields are attacker-controlled, an unauthenticated remote client can inject arbitrary header names/values (e.g. `X-Forwarded-For`, internal-auth headers) that a fronting proxy sanitized from the request-header section, bypassing header-based trust decisions in the application.\n\n  ### Impact\n  Any http4s application using `BlazeServerBuilder` over HTTP/1.1 whose routes or middleware trust proxy-set headers (e.g., `X-Forwarded-For`, `X-Real-IP`, `X-Forwarded-Host`, org-internal auth headers) is affected. Where a fronting proxy strips/normalizes those headers but forwards chunked bodies with trailers intact, an attacker can spoof client IP for allow-lists/rate-limits/audit, forge the `https` scheme, or inject internal-auth headers. A promoted `Connection: close` trailer is also honored, allowing attacker-controlled termination of pooled backend connections.\n\n  ### Workarounds\n  Deploy behind a proxy that removes trailer fields (or rejects requests that use trailers) before forwarding; until patched, avoid trust decisions based on headers that a proxy is relied upon to sanitize.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.http4s:blaze-http_2.13"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.23.18"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.23.17"
    }
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.http4s:blaze-http_2.12"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.23.18"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.23.17"
    }
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.http4s:blaze-http_3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.23.18"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.23.17"
    }
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.http4s:blaze-http_3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.0.0-M1"
      }, {
        "fixed" : "1.0.0-M42"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.http4s:blaze-http_2.13"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.0.0-M1"
      }, {
        "fixed" : "1.0.0-M42"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.0.0-M41"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/http4s/blaze/security/advisories/GHSA-46q4-43ph-c6fr"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/http4s/blaze/commit/ef3e666c146cfc16cb6603f1fc3c464daab4a24f"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/http4s/blaze"
  }, {
    "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-444" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-24T22:26:48Z",
    "nvd_published_at" : null
  }
}