# 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. - **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 21 Apr 2026 - **Updated:** 22 May 2026 - **Also known as:** CLEANSTART-2026-UI10829, GHSA-rx35-6rhx-7858, GO-2026-5643 ## 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 (Improper Limitation of a Pathname to a Restricted Directory) ## 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 | Ecosystem | 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 | | `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: 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. ## 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](https://insights.sbomify.com/CVE-2026-33211/): Tekton Pipelines git resolver has path traversal that allows reading arbitrary files from the resolver pod (critical 9.6) - [CVE-2026-40161](https://insights.sbomify.com/CVE-2026-40161/): Tekton Pipelines: Git resolver API mode leaks system-configured API token to user-controlled serverURL (high 7.7) - [CVE-2026-40938](https://insights.sbomify.com/CVE-2026-40938/): Tekton Pipelines: Git Resolver Unsanitized Revision Parameter Enables git Argument Injection Leading to RCE (high 7.5) - [CVE-2026-25542](https://insights.sbomify.com/CVE-2026-25542/): Tekton Pipelines: VerificationPolicy regex pattern bypass via substring matching (medium 6.5) - [CVE-2026-40924](https://insights.sbomify.com/CVE-2026-40924/): Tekton Pipelines: HTTP Resolver Unbounded Response Body Read Enables Denial of Service via Memory Exhaustion (medium 6.5) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-40923 and fix it if it is affected. What it is: 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. Exploitation: There is no known exploitation of CVE-2026-40923 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/tektoncd/pipeline (Go): affected from 1.0.0; fixed in 1.0.2, 1.3.4, 1.6.2, 1.9.3, 1.11.1 - github.com/tektoncd/pipeline (Go): affected from 1.0.0; fixed in 1.0.2 - github.com/tektoncd/pipeline (Go): affected from 1.0.0; fixed in 1.0.2 - github.com/tektoncd/pipeline (Go): affected from 1.10.0; fixed in 1.11.1 - github.com/tektoncd/pipeline (Go): affected from 1.10.0; fixed in 1.11.1 - github.com/tektoncd/pipeline (Go): affected from 1.2.0; fixed in 1.3.4 - github.com/tektoncd/pipeline (Go): affected from 1.2.0; fixed in 1.3.4 - github.com/tektoncd/pipeline (Go): affected from 1.4.0; fixed in 1.6.2 - github.com/tektoncd/pipeline (Go): affected from 1.4.0; fixed in 1.6.2 - github.com/tektoncd/pipeline (Go): affected from 1.7.0; fixed in 1.9.3 - github.com/tektoncd/pipeline (Go): affected from 1.7.0; fixed in 1.9.3 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-40923/ (Markdown: https://insights.sbomify.com/CVE-2026-40923/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40923 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40923 - OSV: https://osv.dev/vulnerability/CVE-2026-40923 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-40923/ Summaries are generated and may contain mistakes; the official description above is the record.