GHSA-46wh-3698-f2cx — v2
GHSA-46wh-3698-f2cx is a security vulnerability in github.com/traefik/traefik/v2. A fix is available for github.com/traefik/traefik/v2 — see the affected versions and patch details below.
Traefik: Deny Rule Bypass via Unauthenticated Malicious gRPC Requests in gRPC-Go Dependency (CVE-2026-33186)
Real-World Exposure
github.com/traefik/traefik/v2🐹github.com/traefik/traefik/v3🐹github.com/traefik/traefik/v3Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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.
Patches
- https://github.com/traefik/traefik/releases/tag/v2.11.42
- https://github.com/traefik/traefik/releases/tag/v3.6.12
- https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3
For more information
If there are any questions or comments about this advisory, please open an issue.
<details> <summary>Original Description</summary>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
Details
As described in https://github.com/advisories/GHSA-p77j-4mvh-x3m3
PoC
Update library version in https://github.com/traefik/traefik/blob/67c64ed9b25fbb90f1086977a62827133a7aa01b/go.mod#L108
Impact
Is described in https://github.com/advisories/GHSA-p77j-4mvh-x3m3
</details>Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/traefik/traefik/v2 | all versions | 2.11.42go get github.com/traefik/traefik/v2@v2.11.42 |
| 🐹Go | github.com/traefik/traefik/v3 | ≥ 3.0.0-beta3&&< 3.6.12 | 3.6.12go get github.com/traefik/traefik/v3@v3.6.12 |
| 🐹Go | github.com/traefik/traefik/v3 | ≥ 3.7.0-ea.1&&< 3.7.0-ea.3 | 3.7.0-ea.3go get github.com/traefik/traefik/v3@v3.7.0-ea.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/traefik/traefik/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/traefik/traefik/v2 to 2.11.42 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-46wh-3698-f2cx is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-46wh-3698-f2cx can be triaged on real exposure rather than presence alone.
Tailored to GHSA-46wh-3698-f2cx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-46wh-3698-f2cx in your dependencies?
O3 Security finds GHSA-46wh-3698-f2cx across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.