Executive brief
Tekton Pipelines is a framework used to automate software build and deployment processes. A security flaw allows users with basic access to bypass folder restrictions and mount storage volumes into protected internal system directories. This could allow an attacker to tamper with build results, modify scripts before they run, or interfere with the pipeline's internal coordination, potentially compromising the integrity of the software delivery process.
Technical details
A path traversal vulnerability exists in Tekton Pipelines' VolumeMount validation logic. The system attempts to restrict mounts to internal '/tekton/' paths but fails to normalize input using 'filepath.Clean' before performing a 'strings.HasPrefix' check. An authenticated attacker with permissions to create Tasks or TaskRuns can provide a path such as '/tekton/home/../results' which bypasses the prefix check but resolves to the restricted '/tekton/results' directory at runtime. This allows for the unauthorized reading or writing of internal execution state, including task results and step scripts. The issue is fixed in versions 1.0.2, 1.3.4, 1.6.2, 1.9.3, and 1.11.1.
Affected products
- Tekton Tekton Pipelines >= 1.0.0, < 1.0.2; >= 1.1.0, < 1.3.4; >= 1.4.0, < 1.6.2; >= 1.7.0, < 1.9.3; >= 1.10.0, < 1.11.1
Timeline
- 2026-04-21: advisory: GitHub Security Advisory GHSA-rx35-6rhx-7858 published
- 2026-04-21: patched: Version 1.11.1 released with fix
- 2026-04-21: disclosed: CVE-2026-40923 published