CVE-2026-40923 — pipeline
MEDIUMCVE-2026-40923 is a medium-severity (CVSS 5.4) Path Traversal vulnerability in github.com/tektoncd/pipeline. A fix is available for github.com/tektoncd/pipeline — see the affected versions and patch details below.
Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40923.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-40923 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 | 1.11.1go get github.com/tektoncd/pipeline@v1.11.1 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.7.0&&< 1.9.3 | 1.9.3go get github.com/tektoncd/pipeline@v1.9.3 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.4.0&&< 1.6.2 | 1.6.2go get github.com/tektoncd/pipeline@v1.6.2 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.2.0&&< 1.3.4 | 1.3.4go get github.com/tektoncd/pipeline@v1.3.4 |
| 🐹Go | github.com/tektoncd/pipeline | ≥ 1.0.0&&< 1.0.2 | 1.0.2go get github.com/tektoncd/pipeline@v1.0.2 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40923 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2026-40923 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.