CVE-2026-40923 Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check
Attackers can bypass path restrictions to mount volumes in restricted internal directories, potentially reading or modifying sensitive pipeline data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40923?
CVE-2026-40923 is a medium-severity path traversal vulnerability in tektoncd pipeline, published on 21 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Tekton Pipelines project provides k8s-style resources for declaring CI/CD-style pipelines. Starting in version 1.0.0 and prior to versions 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 mounting volumes under restricted /tekton/ internal paths by using .. path traversal components. The restriction check uses strings.HasPrefix without filepath.Clean, so a path like /tekton/home/../results passes validation but resolves to /tekton/results at runtime. Versions 1.0.2, 1.3.4, 1.6.2, 1.9.3, and 1.11.1 fix the issue.
Weakness: CWE-22
Which versions are affected by CVE-2026-40923?
11 open source packages ship an affected version, including github.com/tektoncd/pipeline. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/tektoncd/pipeline Go | From 1.0.0 | 1.0.2, 1.3.4, 1.6.2, 1.9.3, 1.11.1 |
github.com/tektoncd/pipeline Go | From 1.0.0 | 1.0.2 |
github.com/tektoncd/pipeline Go | From 1.0.0 | 1.0.2 |
github.com/tektoncd/pipeline Go | From 1.10.0 | 1.11.1 |
github.com/tektoncd/pipeline Go | From 1.10.0 | 1.11.1 |
github.com/tektoncd/pipeline Go | From 1.2.0 | 1.3.4 |
5 more packages
github.com/tektoncd/pipeline Go | From 1.2.0 | 1.3.4 |
github.com/tektoncd/pipeline Go | From 1.4.0 | 1.6.2 |
github.com/tektoncd/pipeline Go | From 1.4.0 | 1.6.2 |
github.com/tektoncd/pipeline Go | From 1.7.0 | 1.9.3 |
github.com/tektoncd/pipeline Go | From 1.7.0 | 1.9.3 |
Products include Linuxfoundation Tekton Pipelines.
How do I fix CVE-2026-40923?
Upgrade github.com/tektoncd/pipeline to a fixed version for your release line: 1.0.2, 1.3.4, 1.6.2 or 1.9.3.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-40923 being exploited?
There is no known exploitation of CVE-2026-40923 in the wild and no public exploit code.
Other vulnerabilities in tektoncd pipeline
- CVE-2026-33211 Tekton Pipelines git resolver has path traversal that allows reading arbitrary files from the resolver pod
- CVE-2026-40161 Tekton Pipelines: Git resolver API mode leaks system-configured API token to user-controlled serverURL
- CVE-2026-40938 Tekton Pipelines: Git Resolver Unsanitized Revision Parameter Enables git Argument Injection Leading to RCE
- CVE-2026-25542 Tekton Pipelines: VerificationPolicy regex pattern bypass via substring matching
- CVE-2026-40924 Tekton Pipelines: HTTP Resolver Unbounded Response Body Read Enables Denial of Service via Memory Exhaustion
Sources
Also known as CLEANSTART-2026-UI10829, GHSA-rx35-6rhx-7858, GO-2026-5643.