CVE-2026-33747
BuildKit's Malicious frontend can cause file escape outside of storage root in github.com/moby/buildkit
Description
BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. Prior to version 0.28.1, when using a custom BuildKit frontend, the frontend can craft an API message that causes files to be written outside of the BuildKit state directory for the execution context. The issue has been fixed in v0.28.1. The vulnerability requires using an untrusted BuildKit frontend set with `#syntax` or `--build-arg BUILDKIT_SYNTAX`. Using these options with a well-known frontend image like `docker/dockerfile` is not affected.
How to fix CVE-2026-33747
To remediate CVE-2026-33747, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 0.28.1 or later
- —upgrade to 0.28.1 or later
Is CVE-2026-33747 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0
- from 0, < 0.28.1
- from 0, < 0.28.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |