Impact
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.
Patches
The issue has been fixed in v0.12.5
Workarounds
Avoid using BuildKit frontend from an untrusted source or building an untrusted Dockerfile containing cache mounts with --mount=type=cache,source=... options.
References
https://www.openwall.com/lists/oss-security/2019/05/28/1
rmcnamara-snyk Reporter
Impact
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.
Patches
The issue has been fixed in v0.12.5
Workarounds
Avoid using BuildKit frontend from an untrusted source or building an untrusted Dockerfile containing cache mounts with
--mount=type=cache,source=...options.References
https://www.openwall.com/lists/oss-security/2019/05/28/1