CVE-2026-33747

BuildKit vulnerable to malicious frontend causing file escape outside of storage root

CVSS 3.1 8.4 HIGHEUVD CVSS 3.1 8.4 CVSS 3.1 · [email protected] · Secondary 8.4 HIGHCVSS 3.1 · [email protected] · Primary 9.8 CRITICALCVSS_V3 Publisher rating HIGHFixed by github.com/moby/buildkit 0.28.1osv · severity unknownFixed by github.com/moby/buildkit 0.28.1KEV status unknown

Original advisory

cve-program · CVE-2026-33747

Published

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.

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euvd · EUVD-2026-16518

Published

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nvd · CVE-2026-33747

Published

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osv · GHSA-4c29-8rgm-jvjj

Published

### Impact 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. ### Patches The issue has been fixed in v0.28.1+ ### Workarounds Issue 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.

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osv · GO-2026-4858

Published

BuildKit's Malicious frontend can cause file escape outside of storage root in github.com/moby/buildkit

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Affected versions, risk and source history

Exploitation and risk

Source status

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Risk history

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Advisory history

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15 Nov 2026 10:04:37 UTC