GHSA-hrhx-6h34-j5hc
HIGHSkip the router TLS configuration when the host header is an FQDN
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/traefik/traefik/v2Real-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
Impact
People that configure mTLS between Traefik and clients.
For a request, the TLS configuration choice can be different than the router choice, which implies the use of a wrong TLS configuration.
-
When sending a request using FQDN handled by a router configured with a dedicated TLS configuration, the TLS configuration falls back to the default configuration that might not correspond to the configured one.
-
If the CNAME flattening is enabled, the selected TLS configuration is the SNI one and the routing uses the CNAME value, so this can skip the expected TLS configuration.
Patches
Traefik v2.6.x: https://github.com/traefik/traefik/releases/tag/v2.6.1
Workarounds
Add the FDQN to the host rule:
Example:
whoami:
image: traefik/whoami:v1.7.1
labels:
traefik.http.routers.whoami.rule: Host(`whoami.example.com`, `whoami.example.com.`)
traefik.http.routers.whoami.tls: true
traefik.http.routers.whoami.tls.options: mtls@file
There is no workaround if the CNAME flattening is enabled.
For more information
If you have any questions or comments about this advisory, please open an issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/traefik/traefik/v2 | all versions | 2.6.1 |
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/traefik/traefik/v2 to 2.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hrhx-6h34-j5hc 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 pinpoints whether GHSA-hrhx-6h34-j5hc is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-hrhx-6h34-j5hc. 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-hrhx-6h34-j5hc in your dependencies?
O3 detects GHSA-hrhx-6h34-j5hc across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.