CVE-2026-15788: CWE-59: Improper Link Resolution Before File Access ('Link Following') in moby BuildKit
CVE-2026-15788 is a medium severity vulnerability in moby BuildKit affecting Windows Container on Windows (WCOW) workers. The issue arises because BuildKit's cache mount source= selector does not detect NTFS directory junctions inside the cache root. This flaw allows a build authored by an untrusted user on a WCOW-configured BuildKit daemon to read arbitrary host files accessible to the daemon process.
AI Analysis
Technical Summary
BuildKit's cache mount source= selector on Windows Container on Windows (WCOW) workers fails to detect NTFS directory junctions placed inside the cache root. This improper link resolution (CWE-59) can be exploited by an untrusted user to cause the BuildKit daemon to read arbitrary files on the host system that are reachable by the daemon process. The vulnerability is specific to Windows environments using WCOW workers and involves the handling of NTFS directory junctions within the cache mount source path.
Potential Impact
An untrusted user with the ability to author builds on a WCOW-configured BuildKit daemon can read arbitrary files on the host system that the daemon process can access. This could lead to unauthorized disclosure of sensitive information from the host. There is no indication of privilege escalation or remote code execution from the provided data.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary mitigation is currently documented. Until a fix is available, restrict build authoring permissions to trusted users only on WCOW-configured BuildKit daemons to prevent exploitation.
CVE-2026-15788: CWE-59: Improper Link Resolution Before File Access ('Link Following') in moby BuildKit
Description
CVE-2026-15788 is a medium severity vulnerability in moby BuildKit affecting Windows Container on Windows (WCOW) workers. The issue arises because BuildKit's cache mount source= selector does not detect NTFS directory junctions inside the cache root. This flaw allows a build authored by an untrusted user on a WCOW-configured BuildKit daemon to read arbitrary host files accessible to the daemon process.
CVSS v4.0
Score 5.6medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
BuildKit's cache mount source= selector on Windows Container on Windows (WCOW) workers fails to detect NTFS directory junctions placed inside the cache root. This improper link resolution (CWE-59) can be exploited by an untrusted user to cause the BuildKit daemon to read arbitrary files on the host system that are reachable by the daemon process. The vulnerability is specific to Windows environments using WCOW workers and involves the handling of NTFS directory junctions within the cache mount source path.
Potential Impact
An untrusted user with the ability to author builds on a WCOW-configured BuildKit daemon can read arbitrary files on the host system that the daemon process can access. This could lead to unauthorized disclosure of sensitive information from the host. There is no indication of privilege escalation or remote code execution from the provided data.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary mitigation is currently documented. Until a fix is available, restrict build authoring permissions to trusted users only on WCOW-configured BuildKit daemons to prevent exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Docker
- Date Reserved
- 2026-07-14T19:25:38.521Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a5e7dae2a4a8d5989a50ded
Added to database: 07/20/2026, 19:57:34 UTC
Last enriched: 07/20/2026, 20:13:12 UTC
Last updated: 07/21/2026, 03:50:00 UTC
Views: 7
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