CVE-2026-18171: CWE-863: Incorrect Authorization in Docker Docker Sandboxes
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.
AI Analysis
Technical Summary
Docker Sandboxes (sbx) incorrectly enforces read-only access on runtime host mounts by applying the restriction only to the in-guest container bind. The virtio-fs host-edge grant is added to the sandbox's policy-share allowlist without specifying access mode, resulting in the shared-export path remaining writable. Consequently, unprivileged code within the sandbox can discover the shared-export path and write to a host directory that the operator mounted as read-only, violating intended access controls.
Potential Impact
An attacker with unprivileged code execution inside the sandbox can write to host directories that were intended to be read-only, potentially leading to unauthorized modification of host files. This breaks the expected access control model and could facilitate privilege escalation or persistence mechanisms depending on the host directory targeted.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, operators should carefully review and limit the use of host mounts with read-only intent in Docker Sandboxes and monitor for any unusual activity related to host directory writes from containers.
CVE-2026-18171: CWE-863: Incorrect Authorization in Docker Docker Sandboxes
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.
CVSS v4.0
Score 5.7medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Docker Sandboxes (sbx) incorrectly enforces read-only access on runtime host mounts by applying the restriction only to the in-guest container bind. The virtio-fs host-edge grant is added to the sandbox's policy-share allowlist without specifying access mode, resulting in the shared-export path remaining writable. Consequently, unprivileged code within the sandbox can discover the shared-export path and write to a host directory that the operator mounted as read-only, violating intended access controls.
Potential Impact
An attacker with unprivileged code execution inside the sandbox can write to host directories that were intended to be read-only, potentially leading to unauthorized modification of host files. This breaks the expected access control model and could facilitate privilege escalation or persistence mechanisms depending on the host directory targeted.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, operators should carefully review and limit the use of host mounts with read-only intent in Docker Sandboxes and monitor for any unusual activity related to host directory writes from containers.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-q3q4-c92f-m955
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-18171"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 4.0
Threat ID: 6a7c9b1ebf8831d539cda2bb
Added to database: 08/12/2026, 16:11:10 UTC
Last enriched: 08/12/2026, 16:31:56 UTC
Last updated: 08/13/2026, 01:32:26 UTC
Views: 5
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