CVE-2026-120307 (GCVE-0-2026-120307)

Vulnerability from cvelistv5 – Published: 2026-11-01 12:49 – Updated: 2026-11-01 12:49
VLAI
Title
Beta9 container escape via unvalidated sandbox file paths
Summary
The Beta9 worker serves the sandbox file API from outside the container. getHostPathFromContainerPath turns the tenant's container path into a worker path. If the unresolved path starts with a mount destination, including the default upload mount at /tmp/.beta9, the remainder is joined onto that mount's source with filepath.Join, which cleans parent-directory segments after the prefix check. A long enough run of those segments names any absolute path on the worker. A path that matches no mount is joined onto the container root and opened in the worker's own filesystem, so an absolute symbolic link such as /var/run pointing at /run is followed against the worker root. Upload, download, stat, list, find-in-files, replace-in-files, and delete-file all call this helper. A tenant with a workspace token and one running sandbox can read, write, list, and delete files on the hosting worker as root, including files of other tenants on that machine. A read-only proof downloaded the worker pod's Kubernetes service account token through the file API for a path that did not exist inside the sandbox. In the shipped remote-node manifests that service account is bound to cluster-admin. Fixed in worker 0.1.756: sandbox file operations and workspace sync open paths with os.OpenRoot, so parent-directory and symlink lookups stay inside the container root or the mount source.
Severity
9.9 (Critical)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE
  • CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
  • CWE-23 - Relative Path Traversal
  • CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Assigner
JFROG CNA under the mitre root
CNA scorecard B 76/100 over 66 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
beam-cloud Beta9 worker Affected: 0 , < 0.1.756 (semver)
guessed Create a notification for this product.
Credits
Natan Nehorai JFrog Security Research
Show details on NVD website
To clipboard 

{
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    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/beam-cloud/beta9/releases",
          "defaultStatus": "unaffected",
          "packageName": "github.com/beam-cloud/beta9",
          "product": "Beta9 worker",
          "programFiles": [
            "pkg/worker/container_server.go",
            "pkg/worker/lifecycle.go",
            "pkg/types/worker.go"
          ],
          "repo": "git://github.com/beam-cloud/beta9",
          "vendor": "beam-cloud",
          "versions": [
            {
              "lessThan": "0.1.756",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Natan Nehorai"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "JFrog Security Research"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
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              "value": "\u003cp\u003eThe Beta9 worker serves the sandbox file API from outside the container. getHostPathFromContainerPath turns the tenant\u0027s container path into a worker path. If the unresolved path starts with a mount destination, including the default upload mount at /tmp/.beta9, the remainder is joined onto that mount\u0027s source with filepath.Join, which cleans parent-directory segments after the prefix check. A long enough run of those segments names any absolute path on the worker. A path that matches no mount is joined onto the container root and opened in the worker\u0027s own filesystem, so an absolute symbolic link such as /var/run pointing at /run is followed against the worker root. Upload, download, stat, list, find-in-files, replace-in-files, and delete-file all call this helper. A tenant with a workspace token and one running sandbox can read, write, list, and delete files on the hosting worker as root, including files of other tenants on that machine. A read-only proof downloaded the worker pod\u0027s Kubernetes service account token through the file API for a path that did not exist inside the sandbox. In the shipped remote-node manifests that service account is bound to cluster-admin. Fixed in worker 0.1.756: sandbox file operations and workspace sync open paths with os.OpenRoot, so parent-directory and symlink lookups stay inside the container root or the mount source.\u003c/p\u003e"
            }
          ],
          "value": "The Beta9 worker serves the sandbox file API from outside the container. getHostPathFromContainerPath turns the tenant\u0027s container path into a worker path. If the unresolved path starts with a mount destination, including the default upload mount at /tmp/.beta9, the remainder is joined onto that mount\u0027s source with filepath.Join, which cleans parent-directory segments after the prefix check. A long enough run of those segments names any absolute path on the worker. A path that matches no mount is joined onto the container root and opened in the worker\u0027s own filesystem, so an absolute symbolic link such as /var/run pointing at /run is followed against the worker root. Upload, download, stat, list, find-in-files, replace-in-files, and delete-file all call this helper. A tenant with a workspace token and one running sandbox can read, write, list, and delete files on the hosting worker as root, including files of other tenants on that machine. A read-only proof downloaded the worker pod\u0027s Kubernetes service account token through the file API for a path that did not exist inside the sandbox. In the shipped remote-node manifests that service account is bound to cluster-admin. Fixed in worker 0.1.756: sandbox file operations and workspace sync open paths with os.OpenRoot, so parent-directory and symlink lookups stay inside the container root or the mount source."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.9,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "Tenant with a workspace token and a running sandbox on a worker that serves the sandbox file API"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-23",
              "description": "CWE-23: Relative Path Traversal",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "CWE-59: Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-01T12:49:51.981Z",
        "orgId": "48a46f29-ae42-4e1d-90dd-c1676c1e5e6d",
        "shortName": "JFROG"
      },
      "references": [
        {
          "name": "Beta9 repository",
          "tags": [
            "product"
          ],
          "url": "https://github.com/beam-cloud/beta9"
        },
        {
          "name": "Handle sandbox edge cases (fix pull request)",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/beam-cloud/beta9/pull/1897"
        },
        {
          "name": "Fix commit a28bf12",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/beam-cloud/beta9/commit/a28bf12cf0007c792a25d8ed282b4e8bf6f30393"
        },
        {
          "name": "worker-0.1.756",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/beam-cloud/beta9/releases/tag/worker-0.1.756"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eUpgrade the Beta9 worker to 0.1.756 or later. Sandbox file APIs and workspace sync use os.OpenRoot, so parent-directory segments and symbolic links stay inside the container root or the mount source. File operations refuse read-only mounts and do not write through a symlink swapped in after path resolution. The fix is commit a28bf12 (pull request 1897), released as worker-0.1.756 on 2026-09-15.\u003c/p\u003e"
            }
          ],
          "value": "Upgrade the Beta9 worker to 0.1.756 or later. Sandbox file APIs and workspace sync use os.OpenRoot, so parent-directory segments and symbolic links stay inside the container root or the mount source. File operations refuse read-only mounts and do not write through a symlink swapped in after path resolution. The fix is commit a28bf12 (pull request 1897), released as worker-0.1.756 on 2026-09-15."
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "timeline": [
        {
          "lang": "en",
          "time": "2026-09-15T04:03:00.000Z",
          "value": "Fix merged in pull request 1897 (commit a28bf12)"
        },
        {
          "lang": "en",
          "time": "2026-09-15T04:03:00.000Z",
          "value": "Fixed release worker-0.1.756 published. No vendor security advisory was filed with the pull request."
        }
      ],
      "title": "Beta9 container escape via unvalidated sandbox file paths",
      "x_generator": {
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  },
  "cveMetadata": {
    "assignerOrgId": "48a46f29-ae42-4e1d-90dd-c1676c1e5e6d",
    "assignerShortName": "JFROG",
    "cveId": "CVE-2026-120307",
    "datePublished": "2026-11-01T12:49:51.981Z",
    "dateReserved": "2026-11-01T12:45:12.430Z",
    "dateUpdated": "2026-11-01T12:49:51.981Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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                "defaultStatus": "unaffected",
                "packageName": "github.com/beam-cloud/beta9",
                "product": "Beta9 worker",
                "programFiles": [
                  "pkg/worker/container_server.go",
                  "pkg/worker/lifecycle.go",
                  "pkg/types/worker.go"
                ],
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                "vendor": "beam-cloud",
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                    "version": "0",
                    "versionType": "semver"
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        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "The Beta9 worker serves the sandbox file API from outside the container. getHostPathFromContainerPath turns the tenant\u0027s container path into a worker path. If the unresolved path starts with a mount destination, including the default upload mount at /tmp/.beta9, the remainder is joined onto that mount\u0027s source with filepath.Join, which cleans parent-directory segments after the prefix check. A long enough run of those segments names any absolute path on the worker. A path that matches no mount is joined onto the container root and opened in the worker\u0027s own filesystem, so an absolute symbolic link such as /var/run pointing at /run is followed against the worker root. Upload, download, stat, list, find-in-files, replace-in-files, and delete-file all call this helper. A tenant with a workspace token and one running sandbox can read, write, list, and delete files on the hosting worker as root, including files of other tenants on that machine. A read-only proof downloaded the worker pod\u0027s Kubernetes service account token through the file API for a path that did not exist inside the sandbox. In the shipped remote-node manifests that service account is bound to cluster-admin. Fixed in worker 0.1.756: sandbox file operations and workspace sync open paths with os.OpenRoot, so parent-directory and symlink lookups stay inside the container root or the mount source."
          }
        ],
        "id": "CVE-2026-120307",
        "lastModified": "2026-11-01T13:18:01.497",
        "metrics": {
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                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.1,
              "impactScore": 6.0,
              "source": "reefs@jfrog.com",
              "type": "Secondary"
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        "published": "2026-11-01T13:18:01.497",
        "references": [
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            "source": "reefs@jfrog.com",
            "url": "https://github.com/beam-cloud/beta9"
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            "source": "reefs@jfrog.com",
            "url": "https://github.com/beam-cloud/beta9/commit/a28bf12cf0007c792a25d8ed282b4e8bf6f30393"
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            "source": "reefs@jfrog.com",
            "url": "https://github.com/beam-cloud/beta9/pull/1897"
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            "url": "https://github.com/beam-cloud/beta9/releases/tag/worker-0.1.756"
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        "vulnStatus": "Received",
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            "source": "reefs@jfrog.com",
            "type": "Primary"
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  }
}



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