CVE-2026-37236
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.
- Published Aug 28, 2026
- CVSS 9.8 critical
- 0.4% chance of exploitation in the next 30 days (EPSS)
- A fix is available