CVE•Published 2026-09-01•Modified 2026-09-09•0 articles on news•4 live references•NVD data

CVE-2026-84303

Vulnerability data via NVD (ingested)

CVSS v3.1

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EPSS percentile

Exploit Prediction Scoring System · top 77% of all CVEs

Weaknesses (CWE)

CWE-178Improper Handling of Case Sensitivity CWE-863Incorrect Authorization

Description

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.

Timeline

Published 2026-09-01

Modified 2026-09-09

External references

NVD MITRE Exploit-DB VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-84303

Hosts Shodan has explicitly fingerprinted as vulnerable.

More intel sources (5)

Shodan report

vuln:CVE-2026-84303

Country / ASN / product breakdown for the vuln query.

Censys

vulnerabilities.cve_id: CVE-2026-84303

Censys host search filtered to this CVE id.

grep.app

CVE-2026-84303