CVE-2026-15788
WCOW cache mount source selector resolves NTFS junctions outside of cache root
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.
INFO
Published Date :
July 20, 2026, 8:16 p.m.
Last Modified :
July 20, 2026, 8:44 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 686469e6-3ff6-451b-ab8b-cf5b9e89401e | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update BuildKit to the latest version.
- Review BuildKit daemon configuration for WCOW workers.
- Ensure proper permissions on build contexts.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-15788.
| URL | Resource |
|---|---|
| https://github.com/moby/buildkit/security/advisories/GHSA-388v-wmr2-g2v2 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-15788 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-15788
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-15788 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-15788 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 20, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'moby', 'product': 'BuildKit', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.31.2', 'versionType': 'semver'}], 'platforms': ['Windows'], 'defaultStatus': 'unaffected'}] 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. Added CVSS V4.0 AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-59 Added Reference https://github.com/moby/buildkit/security/advisories/GHSA-388v-wmr2-g2v2