| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/traefik/traefik/v2 | < 2.11.42 | 2.11.42 |
| github.com/traefik/traefik/v3 | ≥ 3.0.0-beta3, < 3.6.12≥ 3.7.0-ea.1, < 3.7.0-ea.3 | 3.6.123.7.0-ea.3 |
There is a potential vulnerability in Traefik due to its dependency on an affected version of gRPC-Go (CVE-2026-33186).
A remote, unauthenticated attacker can send gRPC requests with a malformed HTTP/2 :path pseudo-header omitting the mandatory leading slash (e.g., Service/Method instead of /Service/Method). While the server routes such requests correctly, path-based authorization interceptors evaluate the raw non-canonical path and fail to match "deny" rules, allowing the request to bypass the policy entirely if a fallback "allow" rule is present.
If there are any questions or comments about this advisory, please open an issue.
<details> <summary>Original Description</summary>This CVE hits traefik until Version 3.6.11 and 2.11.41. gRPC-Go has an authorization bypass via missing leading slash in :path
As described in https://github.com/advisories/GHSA-p77j-4mvh-x3m3
Update library version in https://github.com/traefik/traefik/blob/67c64ed9b25fbb90f1086977a62827133a7aa01b/go.mod#L108
Is described in https://github.com/advisories/GHSA-p77j-4mvh-x3m3
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