Starting with Tekton Pipelines v1.0.0 and in all releases prior to the patch releases 1.0.2, 1.3.4, 1.6.2, 1.9.3, and 1.11.1, a validation bypass in the VolumeMount path restriction allows a volume to be mounted under the protected /tekton/ internal directories by using '..' path traversal components. The check incorrectly relies on strings.HasPrefix without normalizing the path, so inputs such as /tekton/home/../results pass validation but resolve to /tekton/results at runtime. This can expose internal data or allow an attacker to place malicious files in locations that the pipeline assumes are safe, potentially compromising pipeline integrity and confidentiality of secret data.

Tekton Pipelines (tektoncd:pipeline). All releases prior to 1.11.1 are affected. The vulnerability is fixed starting with pipeline release v1.11.1.

The CVSS score of 5.4 indicates moderate severity. The EPSS score of <1% indicates a very low but nonzero probability of exploitation, and the vulnerability is not listed in the CISA KEV catalog. Exploitation requires the ability to supply a task definition (or other resource) that contains a VolumeMount with a path designed to traverse beyond /tekton/. The attacker does not need network access to the host; the vulnerability is local to the Kubernetes cluster where Tekton Pipelines is running.