CVE-2026-18171
Received Received - Intake

Docker Sandboxes virtio-fs Host Directory Write Access

Publication date: 2026-08-12

Last updated on: 2026-08-12

Assigner: Docker Inc.

Description
Docker Sandboxes (sbx) applies the read-only intent of a runtime host mount to the in-guest container bind only: the underlying virtio-fs host-edge grant is added to the sandbox's policy-share allowlist with no access mode. The directory stays writable at its shared-export path, so unprivileged code inside the sandbox can derive that path and write to a host directory the operator attached read-only.

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Meta Information

Published
2026-08-12
Last Modified
2026-08-12
Generated
2026-08-12
AI Q&A
2026-08-12
EPSS Evaluated
N/A
NVD
CVE-2026-18171
EUVD
EUVD-2026-57236

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
docker docker *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

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Executive Summary

Docker Sandboxes (sbx) has a vulnerability where read-only host mounts are incorrectly applied. The sandbox's policy-share allowlist grants access to a host directory marked read-only, but the underlying virtio-fs export remains writable. Unprivileged code inside the sandbox can exploit this to write to host directories the operator intended to be read-only.

Impact Analysis

This vulnerability allows attackers within a sandbox to modify files on the host system despite read-only restrictions. It could lead to unauthorized data changes, privilege escalation, or compromise of sensitive host files, potentially affecting system integrity and security.

Compliance Impact

This vulnerability could violate compliance requirements by enabling unauthorized write access to sensitive data on the host. GDPR and HIPAA mandate strict data protection and access controls; a breach of read-only restrictions may result in non-compliance, legal penalties, and reputational damage.

Mitigation Strategies

Update Docker Sandboxes to the latest version and review filesystem policies in the Docker Admin Console to restrict write access to host directories. Ensure sandbox policies explicitly deny write operations to shared paths.

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