Vulnerability · Published Aug 28, 2026 · Assigned by mitre
CVE-2026-37236
Critical 9.8
In plain English
A critical-severity authorization bypass via user-controlled key in the golang-github-grpc-ecosystem-grpc-gateway package (Debian). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
grpc-gateway v2.28.0 is vulnerable to Incorrect Access Control. The application processes the X-HTTP-Method-Override header in ServeMux.ServeHTTP without restricting allowed methods. When a POST request with Content-Type application/x-www-form-urlencoded includes this header, the request method is rewritten to an arbitrary attacker-supplied value before routing. This allows bypassing method-based access controls enforced by upstream proxies or WAFs.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | golang-github-grpc-ecosystem-grpc-gateway | no fix listed | DEBIAN-CVE-2026-37236 |
| Debian:13 | golang-github-grpc-ecosystem-grpc-gateway | no fix listed | DEBIAN-CVE-2026-37236 |
| Debian:14 | golang-github-grpc-ecosystem-grpc-gateway | 2.30.0-1 | DEBIAN-CVE-2026-37236 |
| Ubuntu:22.04:LTS | golang-github-grpc-ecosystem-grpc-gateway | no fix listed | UBUNTU-CVE-2026-37236 |
| Ubuntu:24.04:LTS | golang-github-grpc-ecosystem-grpc-gateway | no fix listed | UBUNTU-CVE-2026-37236 |
| Ubuntu:26.04:LTS | golang-github-grpc-ecosystem-grpc-gateway | no fix listed | UBUNTU-CVE-2026-37236 |
| Ubuntu:26.10 | golang-github-grpc-ecosystem-grpc-gateway | no fix listed | UBUNTU-CVE-2026-37236 |
Affected products (as reported)
Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H