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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.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.4%top 62.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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

EcosystemPackageFixed inAdvisory
Debian:12golang-github-grpc-ecosystem-grpc-gatewayno fix listedDEBIAN-CVE-2026-37236
Debian:13golang-github-grpc-ecosystem-grpc-gatewayno fix listedDEBIAN-CVE-2026-37236
Debian:14golang-github-grpc-ecosystem-grpc-gateway2.30.0-1DEBIAN-CVE-2026-37236
Ubuntu:22.04:LTSgolang-github-grpc-ecosystem-grpc-gatewayno fix listedUBUNTU-CVE-2026-37236
Ubuntu:24.04:LTSgolang-github-grpc-ecosystem-grpc-gatewayno fix listedUBUNTU-CVE-2026-37236
Ubuntu:26.04:LTSgolang-github-grpc-ecosystem-grpc-gatewayno fix listedUBUNTU-CVE-2026-37236
Ubuntu:26.10golang-github-grpc-ecosystem-grpc-gatewayno fix listedUBUNTU-CVE-2026-37236

Affected products (as reported)

VendorProductVersions
n/a n/a n/a

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References