BuildKit vulnerable to possible race condition with accessing subpaths from cache mountsGHSA-m3r6-h7wv-7xxv
HIGHFix: moby/buildkit#4604GHSA-m3r6-h7wv-7xxv is a high-severity (CVSS 8.7) CWE-362 vulnerability in github.com/moby/buildkit. A fix is available for github.com/moby/buildkit — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-m3r6-h7wv-7xxv.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/moby/buildkitReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. Two malicious build steps running in parallel sharing the same cache mounts with subpaths could cause a race condition that can lead to files from the host system being accessible to the build container. The issue has been fixed in v0.12.5. Workarounds include, avoiding using BuildKit frontend from an untrusted source or building an untrusted Dockerfile containing cache mounts with --mount=type=cache,source=... options.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/moby/buildkit | all versions | 0.12.5go get github.com/moby/buildkit@v0.12.5 |
Affected Products
buildkitmobyprojectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/moby/buildkit, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/moby/buildkit to 0.12.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m3r6-h7wv-7xxv is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability can only be exploited when two containers are being built in parallel within the same cache directory. A concurrent running build that has the target cache directory mounted, needs to replace the target directory with a symbolic link between the time it is checked and actually used. As there is an…
Do not use BuildKit frontends or Dockerfiles from untrusted sources.Source: Red Hat security advisory for GHSA-m3r6-h7wv-7xxv (CC BY 4.0)
Frequently Asked Questions
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