GHSA-7hgc-php5-77qq
HIGHTalos worker join token can be used to get elevated access level to the Talos API
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/talos-systems/talosReal-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
Talos worker nodes use a join token to get accepted into the Talos cluster. A misconfigured Kubernetes environment may allow workloads to access the join token of the worker node. A malicious workload could then use the join token to construct a Talos CSR (certificate signing request). Due to improper validation while signing a worker node CSR, a Talos control plane node might issue a Talos certificate which allows full access to the Talos API to a worker node that presented a maliciously constructed CSR. Accessing the Talos API with full access on a control plane node might reveal sensitive information, which could allow full-level access to the cluster (Kubernetes and Talos PKI, etc.)
In order to exploit the weakness, a Kubernetes workload would need to access the join token, and then construct a specific kind of Talos CSR in order to obtain a privileged certificate. The Talos API join token is stored in the machine configuration on the worker node. When configured correctly, Kubernetes workloads do not have access to the machine configuration, and thus cannot access the token, nor acquire elevated privileges.
It is possible that users have misconfigured Kubernetes in such a way as to allow a workload to access the machine configuration and reveal the join token. Misconfigurations that may allow the machine configuration to be accessed on a worker node by the Kubernetes workload are:
- allowing a
hostPathmount to mount the machine config directly from the host filesystem (hostPathmounts should not be allowed for untrusted workloads, and are disabled by default in recent versions of Talos.) - reading machine configuration from a cloud metadata server from Kubernetes pods with host networking (on cloud platforms, when machine config is stored in the cloud metadata server, and the cloud metadata server doesn't provide enough protection to prevent access from non-host workloads)
Patches
The problem was fixed in Talos 1.2.2.
Workarounds
Enabling the Pod Security Standards mitigates the vulnerability by denying hostPath mounts and host networking by default in the baseline policy. Talos enables Pod Security Admission plugin by default since Talos v1.1.0.
Clusters that don't run untrusted workloads are not affected.
Clusters with correct Pod Security configurations which don't allow hostPath mounts, and secure access to cloud metadata server (or machine configuration is not supplied via cloud metadata server) are not affected.
References
For more information
If you have any questions or comments about this advisory:
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/talos-systems/talos | all versions | 1.2.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/talos-systems/talos. 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/talos-systems/talos to 1.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7hgc-php5-77qq 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-7hgc-php5-77qq 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-7hgc-php5-77qq. 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-7hgc-php5-77qq in your dependencies?
O3 detects GHSA-7hgc-php5-77qq across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.