{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/tektoncd/pipeline"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.10.0"
            },
            {
              "fixed": "1.11.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/tektoncd/pipeline"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.7.0"
            },
            {
              "fixed": "1.9.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/tektoncd/pipeline"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.4.0"
            },
            {
              "fixed": "1.6.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/tektoncd/pipeline"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.2.0"
            },
            {
              "fixed": "1.3.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/tektoncd/pipeline"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.0"
            },
            {
              "fixed": "1.0.2"
            }
          ],
          "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": "2026-04-21T21:16:45Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nA validation bypass in the VolumeMount path restriction allows mounting\nvolumes under restricted `/tekton/` internal paths by using `..` path\ntraversal components. The restriction check uses `strings.HasPrefix`\nwithout `filepath.Clean`, so a path like `/tekton/home/../results`\npasses validation but resolves to `/tekton/results` at runtime.\n\n### Details\n\nTekton Pipelines restricts VolumeMount paths under `/tekton/` (except\n`/tekton/home`) to prevent users from interfering with internal\nexecution state. The validation at\n`pkg/apis/pipeline/v1/container_validation.go` checks mount paths using\n`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\n`/tekton/home/../results` passes both checks. At runtime, the container\nruntime resolves `..` and the actual mount point becomes\n`/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\nmount 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\n_(to be filled: fixed in versions X.Y.Z)_\n\n### Workarounds\n\n- Use admission controllers (OPA/Gatekeeper, Kyverno) to validate that\n  VolumeMount paths do not contain `..` components.\n- In multi-tenant setups, restrict who can create Task and TaskRun\n  resources via RBAC.\n\n### Affected Versions\n\nAll versions through **v1.10.0** (both `v1` and `v1beta1` APIs).\n\n### Acknowledgments\n\nThis vulnerability was reported by @kodareef5.",
  "id": "GHSA-rx35-6rhx-7858",
  "modified": "2026-05-22T15:40:40Z",
  "published": "2026-04-21T20:26:41Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/tektoncd/pipeline/security/advisories/GHSA-rx35-6rhx-7858"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40923"
    },
    {
      "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"
}