{"id":"CVE-2026-84303","title":"gRPC-Go is the Go language implementation of gRPC","summary":"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…","severity":"medium","cwe":["CWE-178","CWE-863"],"vendor":"grpc","product":"google.golang.org/grpc","affected":["google.golang.org/grpc < 1.83.1"],"patched":["google.golang.org/grpc 1.83.1"],"published":"2026-09-01","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:09:13.080","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-84303","references":[{"url":"https://github.com/grpc/grpc-go/commit/db9482836c298f234c896cf82ab68cafc78237f8","label":"security-advisories@github.com"},{"url":"https://github.com/grpc/grpc-go/commit/ebba6f3f1b206e2b4dc4d1d5a96d18430302c2fe","label":"security-advisories@github.com"},{"url":"https://github.com/grpc/grpc-go/pull/9332","label":"security-advisories@github.com"},{"url":"https://github.com/grpc/grpc-go/pull/9335","label":"security-advisories@github.com"},{"url":"https://github.com/grpc/grpc-go/releases/tag/v1.83.1","label":"security-advisories@github.com"},{"url":"https://github.com/grpc/grpc-go/security/advisories/GHSA-qc2q-p7wx-3px3","label":"security-advisories@github.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84303"},{"url":"https://github.com/grpc/grpc-go"},{"url":"https://github.com/advisories/GHSA-qc2q-p7wx-3px3"}],"tags":["nvd","osv","go","ghsa"],"epss":0.00311,"epssPercentile":0.24118,"aliases":["GHSA-qc2q-p7wx-3px3","GO-2026-6441"],"ecosystem":"go","ingestedAt":"2026-09-08T21:11:12.322Z","slug":"CVE-2026-84303","body":"## Overview\n\ngRPC-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-84303)\n\nAffected packages:\n\n- `google.golang.org/grpc < 1.83.1`\n\nPatched in:\n\n- `google.golang.org/grpc 1.83.1`\n\nSource: https://osv.dev/vulnerability/GHSA-qc2q-p7wx-3px3","depth":"sunlit","depthScore":28,"depthScoreParts":{"impact":27.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}