# CVE-2026-103916: Docker Sandboxes sbx cp follows workspace symlinks outside the authorized host directory

Status: published. Published: 2026-11-03. Updated: 2026-11-03.

Docker Sandboxes sbx cp does not safely confine host-side paths to a shared workspace. A malicious sandbox can create or replace a workspace symlink so that a later user-initiated copy reads a host file outside the workspace into the sandbox or writes sandbox-controlled data to a host path outside the workspace with the invoking user's permissions.

## Remediation

- fix: Upgrade Docker Sandboxes to version 0.51.0 or later. (source: CNA: Docker)
- workaround: Until upgrading, do not use sbx cp with a host-side source or destination inside a workspace writable by untrusted sandbox code. Use a host-only path for the copy instead. (source: CNA: Docker)

## Affected products and versions

- Docker / Docker Sandboxes: ≥ 0.28.0; < 0.51.0 (affected, semver). Source: CNA: Docker; platforms: MacOS, Linux, Windows

## Severity and prioritization

- CVSS 4.0: 8.4 (high); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: Docker

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-59

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://docs.docker.com/ai/sandboxes/ (CNA: Docker; product)

- https://docs.docker.com/ai/sandboxes/security/isolation/ (CNA: Docker; technical-description)

- https://github.com/docker/sbx-releases/releases/tag/v0.51.0 (CNA: Docker; release-notes)

## Provenance

- CNA: Docker: https://www.cve.org/CVERecord?id=CVE-2026-103916; retrieved 2026-11-03; source updated 2026-11-03

Revision: 2122345ec0010ff018f59e49c9325671e751a0915faead60733307116034b9d9

Canonical: https://y2.dev/cve/CVE-2026-103916

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