{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.83.1"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "db9482836c298f234c896cf82ab68cafc78237f8"
            },
            {
              "fixed": "ebba6f3f1b206e2b4dc4d1d5a96d18430302c2fe"
            },
            {
              "fixed": "1550d9e0cddb30ce99e61a2102e8294a49461e5e"
            }
          ],
          "repo": "https://github.com/grpc/grpc-go",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qc2q-p7wx-3px3"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-178",
      "CWE-863"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84303.json"
  },
  "details": "gRPC-Go is the Go language implementation of gRPC. Prior to 1.83.1, the xDS RBAC HTTP filter in internal/xds/httpfilter/rbac/rbac.go does not lowercase header matcher names in normalizeHeaderMatcher even though incoming metadata keys are lowercase. A DENY policy using a mixed-case name such as X-Role or User-Agent therefore does not match and fails open, allowing requests that should be rejected. The same case mismatch permits :Scheme or Grpc-Status to evade gRFC A41 validation and prevents Host from being rewritten to :authority. This issue is fixed in version 1.83.1.",
  "id": "CVE-2026-84303",
  "modified": "2026-09-04T03:30:56.458268890Z",
  "published": "2026-09-01T18:14:37.870Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/grpc/grpc-go/releases/tag/v1.83.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84303.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/grpc/grpc-go/security/advisories/GHSA-qc2q-p7wx-3px3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84303"
    },
    {
      "type": "FIX",
      "url": "https://github.com/grpc/grpc-go/commit/db9482836c298f234c896cf82ab68cafc78237f8"
    },
    {
      "type": "FIX",
      "url": "https://github.com/grpc/grpc-go/commit/ebba6f3f1b206e2b4dc4d1d5a96d18430302c2fe"
    },
    {
      "type": "FIX",
      "url": "https://github.com/grpc/grpc-go/pull/9332"
    },
    {
      "type": "FIX",
      "url": "https://github.com/grpc/grpc-go/pull/9335"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "gRPC-Go: xDS RBAC HTTP Filter bypass via mixed-case Header Matching and gRFC A41 validation evasion"
}