CVE-2026-15788

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductMobyproject Buildkit

PublishedJul 20, 2026

First seenJul 20, 2026

Weakness typeCWE-59Improper link resolution

How to fix

Update

mobyproject buildkit0.31.2 or later

Vendor advisories

github.com/moby/buildkit/security/advisories/GHSA-388v-wmr2-g2v2

Affected products

Product	Affected versions	Fixed in
mobyproject buildkit	v < 0.31.2	0.31.2

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