Summary
Talos worker join token can be used to get elevated access level to the Talos API
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]
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)
A file, directory, or other resource is assigned permissions that allow broader access than intended. Typical impact: unauthorized read, modification, or execution of the resource.
CVE-2022-36103 has a CVSS score of 7.2 (High). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.2.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
The problem was fixed in Talos 1.2.2.
Frequently Asked Questions
- What is CVE-2022-36103? CVE-2022-36103 is a high-severity incorrect permission assignment for critical resource vulnerability in github.com/talos-systems/talos (go), affecting versions < 1.2.2. It is fixed in 1.2.2. A file, directory, or other resource is assigned permissions that allow broader access than intended.
- How severe is CVE-2022-36103? CVE-2022-36103 has a CVSS score of 7.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/talos-systems/talos are affected by CVE-2022-36103? github.com/talos-systems/talos (go) versions < 1.2.2 is affected.
- Is there a fix for CVE-2022-36103? Yes. CVE-2022-36103 is fixed in 1.2.2. Upgrade to this version or later.
- Is CVE-2022-36103 exploitable, and should I be worried? Whether CVE-2022-36103 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-36103 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-36103? Upgrade
github.com/talos-systems/talosto 1.2.2 or later.