CVE-2026-33747

High

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.

SeverityHigh
CVSS8.4
Exploit probability—
ProductMobyproject Buildkit
PublishedMar 27, 2026
First seenMar 27, 2026

How to fix

Update
  • mobyproject buildkit0.28.1 or later
  • github.com/moby/buildkit0.28.1 or later

Affected products

ProductAffected versionsFixed in
mobyproject buildkitv < 0.28.10.28.1
github.com/moby/buildkitGov < 0.28.10.28.1

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CVE-2026-33747 · Mobyproject Buildkit · Dark Radar