Vulnerability-Lookup

GHSA-RX35-6RHX-7858

Vulnerability from github – Published: 2026-04-21 20:26 – Updated: 2026-04-21 20:26

Summary

Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check

Details

Summary

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.

Details

Tekton Pipelines restricts VolumeMount paths under /tekton/ (except /tekton/home) to prevent users from interfering with internal execution state. The validation at pkg/apis/pipeline/v1/container_validation.go checks mount paths using strings.HasPrefix without normalizing the path first:

if strings.HasPrefix(vm.MountPath, "/tekton/") &&
    !strings.HasPrefix(vm.MountPath, "/tekton/home") {
    // reject
}

Because /tekton/home is an allowed prefix, a path like /tekton/home/../results passes both checks. At runtime, the container runtime resolves .. and the actual mount point becomes /tekton/results.

The same pattern exists in pkg/apis/pipeline/v1beta1/task_validation.go.

Impact

An authenticated user with Task or TaskRun creation permissions can mount volumes over internal Tekton paths, potentially:

Writing fake task results that downstream pipelines trust
Reading or modifying step scripts before execution
Interfering with entrypoint coordination state

Patches

A patch is available at v1.11.1.

Workarounds

Use admission controllers (OPA/Gatekeeper, Kyverno) to validate that VolumeMount paths do not contain .. components.
In multi-tenant setups, restrict who can create Task and TaskRun resources via RBAC.

Affected Versions

All versions through v1.11.0 (both v1 and v1beta1 APIs).

Acknowledgments

This vulnerability was reported by @kodareef5.

Severity ?

5.4 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.11.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/tektoncd/pipeline"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.11.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40923"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-21T20:26:41Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nA 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.\n\n## Details\n\nTekton Pipelines restricts VolumeMount paths under `/tekton/` (except `/tekton/home`) to prevent users from interfering with internal execution state. The validation at `pkg/apis/pipeline/v1/container_validation.go` checks mount paths using `strings.HasPrefix` without normalizing the path first:\n\n```go\nif strings.HasPrefix(vm.MountPath, \"/tekton/\") \u0026\u0026\n    !strings.HasPrefix(vm.MountPath, \"/tekton/home\") {\n    // reject\n}\n```\n\nBecause `/tekton/home` is an allowed prefix, a path like `/tekton/home/../results` passes both checks. At runtime, the container runtime resolves `..` and the actual mount point becomes `/tekton/results`.\n\nThe same pattern exists in `pkg/apis/pipeline/v1beta1/task_validation.go`.\n\n## Impact\n\nAn authenticated user with Task or TaskRun creation permissions can mount volumes over internal Tekton paths, potentially:\n\n- Writing fake task results that downstream pipelines trust\n- Reading or modifying step scripts before execution\n- Interfering with entrypoint coordination state\n\n## Patches\n\nA patch is available at [v1.11.1](https://github.com/tektoncd/pipeline/releases/tag/v1.11.1).\n\n## Workarounds\n\n- Use admission controllers (OPA/Gatekeeper, Kyverno) to validate that VolumeMount paths do not contain `..` components.\n- In multi-tenant setups, restrict who can create Task and TaskRun resources via RBAC.\n\n## Affected Versions\n\nAll versions through **v1.11.0** (both `v1` and `v1beta1` APIs).\n\n## Acknowledgments\n\nThis vulnerability was reported by [@kodareef5](https://github.com/kodareef5).",
  "id": "GHSA-rx35-6rhx-7858",
  "modified": "2026-04-21T20:26:41Z",
  "published": "2026-04-21T20:26:41Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/tektoncd/pipeline/security/advisories/GHSA-rx35-6rhx-7858"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tektoncd/pipeline"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tektoncd/pipeline/releases/tag/v1.11.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check"
}

CVE-2026-40923 (GCVE-0-2026-40923)

Vulnerability from cvelistv5 – Published: 2026-04-21 20:50 – Updated: 2026-04-22 13:51

Title

Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check

Summary

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.

Severity ?

5.4 (Medium)


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

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M

References

URL

Tags

	https://github.com/tektoncd/pipeline/security/adv…	x_refsource_CONFIRM
	https://github.com/tektoncd/pipeline/releases/tag…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	tektoncd	pipeline	Affected: < 1.11.1

Show details on NVD website

JSON

To clipboard

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  "containers": {
    "adp": [
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        "metrics": [
          {
            "other": {
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                "id": "CVE-2026-40923",
                "options": [
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                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-22T13:50:48.955785Z",
                "version": "2.0.3"
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          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
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          "product": "pipeline",
          "vendor": "tektoncd",
          "versions": [
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            }
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        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
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      "problemTypes": [
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          "url": "https://github.com/tektoncd/pipeline/security/advisories/GHSA-rx35-6rhx-7858"
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          "url": "https://github.com/tektoncd/pipeline/releases/tag/v1.11.1"
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      ],
      "source": {
        "advisory": "GHSA-rx35-6rhx-7858",
        "discovery": "UNKNOWN"
      },
      "title": "Tekton Pipelines: VolumeMount path restriction bypass via missing filepath.Clean in /tekton/ check"
    }
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  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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    "datePublished": "2026-04-21T20:50:53.742Z",
    "dateReserved": "2026-04-15T20:40:15.517Z",
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    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-RX35-6RHX-7858

Summary

Details

Impact

Patches

Workarounds

Affected Versions

Acknowledgments

CVE-2026-40923 (GCVE-0-2026-40923)

Tags

Sightings

Nomenclature