CVE-2026-15788

WCOW cache mount source selector resolves NTFS junctions outside of cache root

Published Jul 20, 2026 CVSS 4.0 · 5.6 Medium EPSS < 1% KEV · Not listed
Description
BuildKit's cache mount source= selector on Windows Container on Windows (WCOW) workers does not detect NTFS directory junctions placed inside the cache root. A build authored by an untrusted user on a WCOW-configured BuildKit daemon can read arbitrary host files reachable to the BuildKit daemon process.

Remediation

Vendor Workaround

Use trusted build sources.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Moby
Moby buildkit
Vendors & Products Moby
Moby buildkit
Type Values Removed Values Added
Description BuildKit's cache mount source= selector on Windows Container on Windows (WCOW) workers does not detect NTFS directory junctions placed inside the cache root. A build authored by an untrusted user on a WCOW-configured BuildKit daemon can read arbitrary host files reachable to the BuildKit daemon process.
Title WCOW cache mount source selector resolves NTFS junctions outside of cache root
Weaknesses CWE-59
References
Metrics cvssV4_0

{'score': 5.6, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Docker
Published
Updated
Jul 21, 2026, 12:40 PM
Reserved
Jul 14, 2026, 7:25 PM
Status
Analyzed
Published
Jul 20, 2026, 8:16 PM
Modified
Oct 24, 2026, 8:10 PM