Incorrect Authorization Affecting github.com/grpc/grpc-go package, versions <1.79.3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published19 Mar 2026
- disclosed18 Mar 2026
- creditMariuszMaik
Introduced: 18 Mar 2026
CVE-2026-33186 Â (opens in a new tab)How to fix?
Upgrade github.com/grpc/grpc-go to version 1.79.3 or higher.
Overview
Affected versions of this package are vulnerable to Incorrect Authorization in the processing of HTTP/2 :path pseudo-headers in handleStream(). An attacker can gain unauthorized access to restricted resources by sending requests with malformed :path headers that omit the leading slash. This is only exploitable if the server uses path-based authorization interceptors, has deny rules that use canonical paths with leading slashes, and has a fallback allow rule in its policy.
Workaround
This vulnerability can be mitigated by adding a validating interceptor that rejects requests with malformed paths, configuring infrastructure (such as reverse proxies) to enforce strict HTTP/2 compliance, or switching to a default-deny authorization policy.