{"id":"DEBIAN-CVE-2026-84303","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.","modified":"2026-09-10T08:47:33.056177352Z","published":"2026-09-01T19:17:30.600Z","upstream":["CVE-2026-84303"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-84303"}],"affected":[{"package":{"name":"golang-google-grpc","ecosystem":"Debian:12","purl":"pkg:deb/debian/golang-google-grpc?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.33.3-2","1.38.0+really1.33.3-1","1.38.0-1","1.38.0-2","1.38.0-3","1.38.0-4","1.38.0-5","1.38.1-1","1.59.0-1","1.60.1-1","1.60.1-2","1.64.0-1","1.64.0-2","1.64.0-3","1.64.0-4","1.64.0-5","1.64.0-6","1.64.0-7","1.66.3-1","1.66.3-2","1.75.1-1","1.79.3-1","1.79.3-1~bpo13+1","1.81.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-84303.json"}},{"package":{"name":"golang-google-grpc","ecosystem":"Debian:13","purl":"pkg:deb/debian/golang-google-grpc?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.64.0-7","1.66.3-1","1.66.3-2","1.75.1-1","1.79.3-1","1.79.3-1~bpo13+1","1.81.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-84303.json"}},{"package":{"name":"golang-google-grpc","ecosystem":"Debian:14","purl":"pkg:deb/debian/golang-google-grpc?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.64.0-7","1.66.3-1","1.66.3-2","1.75.1-1","1.79.3-1","1.79.3-1~bpo13+1","1.81.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-84303.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}