CVE-2026-84303
Last modified
CVE-2026-84303 is a medium-severity vulnerability rated 6.3/10 on the CVSS scale. 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.
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.
Metrics
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
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| grpc | grpc-go | < 1.83.1 |
References
Timeline
- Published
- Last Modified
- Status
- Received
Frequently Asked Questions
What is CVE-2026-84303?
How severe is CVE-2026-84303?
How do I fix CVE-2026-84303?
How Strix Helps
- Uncovering a hidden BOLA in Appsmith's snapshot logicStrix autonomously discovered a BOLA/IDOR vulnerability in Appsmith's snapshot deletion path.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-84269A flaw was found in the AFP backend in gvfs. When mounting a…6.5
- CVE-2026-8427Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Requ…8.8
- CVE-2026-84270A flaw was found in the MTP backend in gvfs. When reading a …4.3
- CVE-2026-8428Concrete CMS 9.5.0 and below emits a CSRF token in the local…8.8
- CVE-2026-8429SPIP versions prior to 4.4.14 contain a remote code executio…8.8
- CVE-2026-8430SPIP versions prior to 4.4.14 contain a remote code executio…9.2
- CVE-2026-84304gRPC-Go is the Go language implementation of gRPC. Prior to …8.7
- CVE-2026-84305sqlparse is a non-validating SQL parser module for Python. P…5.1
- CVE-2026-84306Filament is a collection of full-stack components for accele…6.5
- CVE-2026-8431An administrative user with access to configure webhooks can…9.4
- CVE-2026-8432Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Requ…8.8
- CVE-2026-8433Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Requ…8.8
Are you affected by CVE-2026-84303?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST