CVE-2026-40923: Tekton Pipelines path traversal in VolumeMount validation

CVE-2026-40923 · Severity: medium · CVSS 5.4 · Published 2026-04-21

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.

Technologies: github.com/tektoncd/pipeline (Go), Linuxfoundation Tekton Pipelines, Tekton Pipelines. Vendors: Go, Linuxfoundation, Tekton.

Quick answers

Is CVE-2026-40923 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-40923 being exploited in the wild.
How severe is CVE-2026-40923?
Medium severity, with a CVSS score of 5.4, published 21 April 2026.
Which products and versions are affected?
github.com/tektoncd/pipeline (Go) <= 1.11.0, SEMVER:introduced=1.0.0,fixed=1.0.2,introduced=1.1.0,fixed=1.3.4,introduced=1.4.0,fixed=1.6.2,introduced=1.7.0,fixed=1.9.3,introduced=1.10.0,fixed=1.11.1, SEMVER:introduced=1.10.0,fixed=1.11.1; 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.
Is there a fix for CVE-2026-40923?
Yes. github.com/tektoncd/pipeline (Go): upgrade to 1.11.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-40923 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-40923?
Check whether you run github.com/tektoncd/pipeline (Go), Linuxfoundation Tekton Pipelines or Tekton Pipelines at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/tektoncd/pipeline (Go): upgrade to 1.11.1 or later
    go get github.com/tektoncd/pipeline@v1.11.1

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

Identifiers

  • CVE-2026-40923
  • GHSA-rx35-6rhx-7858
  • GO-2026-5643

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

References

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