Vulnerability · Published Mar 27, 2026 · Assigned by GitHub_M
CVE-2026-33747BuildKit vulnerable to malicious frontend causing file escape outside of storage root
High 8.4
In plain English
A high-severity path traversal in buildkit from moby. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | buildkit | 0.29.0-r0 | ALPINE-CVE-2026-33747 |
| Alpine:v3.23 | docker | 29.3.1-r0 | ALPINE-CVE-2026-33747 |
| Alpine:v3.24 | docker | 29.3.1-r0 | ALPINE-CVE-2026-33747 |
| Debian:12 | docker.io | no fix listed | DEBIAN-CVE-2026-33747 |
| Debian:13 | docker.io | 26.1.5+dfsg1-9+deb13u1 | DEBIAN-CVE-2026-33747 |
| Debian:14 | docker.io | 28.5.2+dfsg4-3 | DEBIAN-CVE-2026-33747 |
| Go | github.com/moby/buildkit | 0.28.1 | GO-2026-4858 |
| Go | github.com/moby/buildkit | 0.28.1 | GHSA-4c29-8rgm-jvjj |
| Ubuntu:25.10 | docker.io | no fix listed | UBUNTU-CVE-2026-33747 |
| Ubuntu:26.04:LTS | docker.io | no fix listed | UBUNTU-CVE-2026-33747 |
| Ubuntu:26.10 | docker.io | no fix listed | UBUNTU-CVE-2026-33747 |
| Ubuntu:22.04:LTS | docker.io-app | 29.1.3-0ubuntu3~22.04.2 | UBUNTU-CVE-2026-33747 |
| Ubuntu:24.04:LTS | docker.io-app | 29.1.3-0ubuntu3~24.04.2 | UBUNTU-CVE-2026-33747 |
| Ubuntu:25.10 | docker.io-app | no fix listed | UBUNTU-CVE-2026-33747 |
| Ubuntu:26.04:LTS | docker.io-app | 29.1.3-0ubuntu4.1 | UBUNTU-CVE-2026-33747 |
| Ubuntu:26.10 | docker.io-app | 29.1.3-0ubuntu5 | UBUNTU-CVE-2026-33747 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://github.com/moby/buildkit/security/advisories/GHSA-4c29-8rgm-jvjj x_refsource_CONFIRM
- https://github.com/moby/buildkit/releases/tag/v0.28.1 x_refsource_MISC