High severity · published Jul 20, 2026
CVE-2026-15788
WCOW cache mount source selector resolves NTFS junctions outside of cache root
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 35% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BU
BuildKit · moby
before 0.31.2 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-15788
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-15788
Vendor Advisory
https://github.com/moby/buildkit/security/advisories/GHSA-388v-wmr2-g2v2
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