CVE-2026-15788: BuildKit's cache mount source= selector on Windows Container on Windows (WCOW) workers does not detect NTFS di

Q: How do I fix CVE-2026-15788?

buildkit: upgrade to 0.31.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-15788 being exploited?

CVE-2026-15788 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-15788 affect?

CVE-2026-15788 affects buildkit. Severity is high (CVSS 7.5). 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 rea

Q: How urgent is CVE-2026-15788?

Priority 45/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADE

CVE-2026-15788 is a high-severity flaw (CVSS 7.5) affecting buildkit. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-59
Published	2026-07-20
Last modified	2026-10-24

Publisher (CNA): Docker Inc. · Vendor: mobyproject

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-20 20:16 UTCPublished CVE record published
2026-10-24 20:10 UTCUpdated Record last modified

mobyproject buildkit UPGRADE

Affected: < 0.31.2

Fixed in: 0.31.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy buildkit || rpm -q buildkit || buildkit --version

2. UPGRADE to 0.31.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade buildkit

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade buildkit

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-15788?

buildkit: upgrade to 0.31.2. Exact commands for each OS are on this page.

Is CVE-2026-15788 being exploited?

CVE-2026-15788 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-15788 affect?

CVE-2026-15788 affects buildkit. Severity is high (CVSS 7.5). 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 rea

How urgent is CVE-2026-15788?

Priority 45/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Windows vulnerabilities

Related CVEs

CVE-2026-15789 HIGH 7.5 UPGRADE A custom client can produce such an upload request to the BuildKit daemon that files can escape from the Build
CVE-2026-15791 HIGH 7.5 UPGRADE A crafted message in the BuildKit low-level build API can be used to remove the contents of the /tmp directory
CVE-2026-15792 HIGH 7.5 UPGRADE A malicious BuildKit client or frontend could craft a request that could lead to BuildKit daemon crashing with
CVE-2026-15793 HIGH 7.5 UPGRADE BuildKit custom frontends or clients using the raw low-level API can set git.checkoutbundle=true when checking

References

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