Vulnerability briefing · 2026-11-01 18:48 IST

CVE-2026-120307

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.

CRITICAL · 9.9Containers / DevOps

Executive briefing

This record describes a reported software or hardware weakness. The description and CVSS rating are source metadata; practical risk depends on whether your environment uses an affected product/version and whether the vulnerable component is reachable and configured in an exploitable way.

Assessment status: No CISA KEV listing is currently recorded in this local feed. This does not prove the vulnerability is not exploited.

Severity & exploitability

9.9 / 10 CVSS

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

Attack vectorN
Attack complexityL
Privileges requiredL
User interactionN
ScopeC
Confidentiality impactH
Integrity impactH
Availability impactH

Impacted products and platforms

Specific affected product configurations are not currently available in the NVD record. Review vendor advisories and validate applicability against your asset inventory.

How it works and what it could affect

The NVD description is the authoritative short summary currently available for this record. A detailed technical mechanism is not inferred when the source record does not provide one.

Weakness classification: CWE-22CWE-23CWE-59

Review the CVSS attack characteristics above to understand whether exploitation is network/local, whether privileges or user interaction are required, and which confidentiality, integrity or availability impacts are scored.

Remediation and recommended response

  1. Identify exposure: compare the affected product and version ranges below with your asset inventory, software bill of materials, endpoint inventory and externally exposed services.
  2. Remediate: review the linked vendor security advisory or patch notes, upgrade to a fixed release, or apply the vendor-provided workaround if an upgrade cannot be completed.
  3. Mitigate while patching: restrict network access to the vulnerable service, disable the affected feature where operationally safe, and monitor vendor/CERT advisories for updated guidance.
  4. Validate: confirm the fixed version or mitigation on representative systems, run a vulnerability rescan, and retain change evidence.

Vendor remediation / security advisories

Exploit intelligence & references

No CISA KEV match is recorded in the latest successful catalog refresh. This is not a guarantee that public proof-of-concept code or exploitation does not exist.

Sources: NVD and CISA KEV when available. Vendor confirmation remains the final authority for fixed versions and workarounds.

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