CVE-2026-40923
MEDIUMCVE-2026-40923 is a medium-severity (CVSS 5.4) Path Traversal vulnerability in github.com/tektoncd/pipeline. O3 Security confirms whether CVE-2026-40923 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check
Blast Radius
github.com/tektoncd/pipeline🐹github.com/tektoncd/pipeline🐹github.com/tektoncd/pipeline🐹github.com/tektoncd/pipeline🐹github.com/tektoncd/pipelineReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.10.0&&< 1.11.1 | 1.11.1 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.7.0&&< 1.9.3 | 1.9.3 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.4.0&&< 1.6.2 | 1.6.2 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.2.0&&< 1.3.4 | 1.3.4 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.0.0&&< 1.0.2 | 1.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/tektoncd/pipeline. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/tektoncd/pipeline to 1.11.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40923 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-40923 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-40923. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40923 in your dependencies?
O3 detects CVE-2026-40923 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.