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.
"}],"value":"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."}],"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 ('Path Traversal')","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 ('Link Following')","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":"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.
"}],"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":{"engine":"Vulnogram 1.0.5"}}},"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"},"nvd":{"publishedDate":"2026-11-01 13:18:01","lastModifiedDate":"2026-11-02 19:35:33","problem_types":["CWE-22","CWE-23","CWE-59","CWE-22 CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')","CWE-23 CWE-23: Relative Path Traversal","CWE-59 CWE-59: Improper Link Resolution Before File Access ('Link Following')"],"metrics":{"cvssMetricV31":[{"source":"reefs@jfrog.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","baseScore":9.9,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.1,"impactScore":6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"120307","Ordinal":"1","Title":"Beta9 container escape via unvalidated sandbox file paths","CVE":"CVE-2026-120307","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"120307","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Beta9 container escape via unvalidated sandbox file paths"}]}}}