Path Traversal in Moby Buildkit
CVE-2026-33747
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.
Vulnerability class: Path Traversal (Directory Traversal)
EPSS: 0.005 (40.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Moby Buildkit — versions < 0.28.1
- Mobyproject Buildkit
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-33747?
- CVE-2026-33747 is a high-severity vulnerability in Moby Buildkit, classified under Path Traversal. CVSS score: 8.4/10. Published 2026-03-27.
- How severe is CVE-2026-33747?
- High severity. CVSS v3 base score is 8.4 out of 10.