CVE-2026-40161 Tekton Pipelines: Git resolver API mode leaks system-configured API token to user-controlled serverURL

High 7.7 Published Updated

Attackers with pipeline creation permissions can exfiltrate system Git API tokens by directing resolver requests to malicious servers.

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-2026-40161?

CVE-2026-40161 is a high-severity 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, the Tekton Pipelines git resolver in API mode sends the system-configured Git API token to a user-controlled serverURL when the user omits the token parameter. A tenant with TaskRun or PipelineRun create permission can exfiltrate the shared API token (GitHub PAT, GitLab token, etc.) by pointing serverURL to an attacker-controlled endpoint. Versions 1.0.2, 1.3.4, 1.6.2, 1.9.3, and 1.11.1 fix the issue.

Weakness: CWE-201

Which versions are affected by CVE-2026-40161?

11 open source packages ship an affected version, including github.com/tektoncd/pipeline. It affects 1 product.

PackageAffectedFixed in
github.com/tektoncd/pipeline GoFrom 1.0.01.0.2, 1.3.4, 1.6.2, 1.9.3, 1.11.1
github.com/tektoncd/pipeline GoFrom 1.0.01.0.2
github.com/tektoncd/pipeline GoFrom 1.0.01.0.2
github.com/tektoncd/pipeline GoFrom 1.10.01.11.1
github.com/tektoncd/pipeline GoFrom 1.10.01.11.1
github.com/tektoncd/pipeline GoFrom 1.2.01.3.4
5 more packages
github.com/tektoncd/pipeline GoFrom 1.2.01.3.4
github.com/tektoncd/pipeline GoFrom 1.4.01.6.2
github.com/tektoncd/pipeline GoFrom 1.4.01.6.2
github.com/tektoncd/pipeline GoFrom 1.7.01.9.3
github.com/tektoncd/pipeline GoFrom 1.7.01.9.3

Products include Linuxfoundation Tekton Pipelines.

How do I fix CVE-2026-40161?

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.

Is CVE-2026-40161 being exploited?

There is no known exploitation of CVE-2026-40161 in the wild and no public exploit code.

Sources

Also known as CLEANSTART-2026-BW27317, GHSA-wjxp-xrpv-xpff, GO-2026-5711.

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