# CVE-2026-33747: docker.io: BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner

CVE-2026-33747 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2026-33747, released March 27, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-33747
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0051
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 27, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | docker.io Debian 13.5 (trixie) | 26.1.5+dfsg1-9+deb13u1 | [DEBIAN-CVE-2026-33747](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33747.md) | Mar 27, 2026 |
| Linux | docker.io Debian 14 | 28.5.2+dfsg4-3 | [DEBIAN-CVE-2026-33747](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33747.md) | Mar 27, 2026 |
| Linux | docker.io Ubuntu 20.04 LTS (focal) | 26.1.3-0ubuntu1~20.04.1+esm2 | [docker.io 26.1.3-0ubuntu1~20.04.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-docker.io-26.1.3-0ubuntu1-20.04.1-esm2.md) | May 15, 2026 |
| Linux | docker.io Ubuntu 22.04.1 LTS (jammy) | 29.1.3-0ubuntu3~22.04.2 | [docker.io 29.1.3-0ubuntu3~22.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-docker.io-29.1.3-0ubuntu3-22.04.2.md) | May 15, 2026 |
| Linux | docker.io Ubuntu 24.04.5 LTS (noble) | 29.1.3-0ubuntu3~24.04.2 | [docker.io 29.1.3-0ubuntu3~24.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-docker.io-29.1.3-0ubuntu3-24.04.2.md) | May 15, 2026 |
| Linux | docker.io Ubuntu 26.04.1 LTS (resolute) | 29.1.3-0ubuntu4.1 | [docker.io 29.1.3-0ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-docker.io-29.1.3-0ubuntu4.1.md) | Apr 21, 2026 |
| Linux | govulncheck-vulndb opensuse-leap 15.6 | 0.0.20260402T184258-150000.1.158.1 | [SUSE-SU-2026:1205-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1205-1.md) | Apr 7, 2026 |
| Linux | govulncheck-vulndb opensuse-leap 16.0 | 0.0.20260723T184607-160000.1.1 | [OPENSUSE-SU-2026:21483-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21483-1.md) | Jul 30, 2026 |
| Linux | tailscale opensuse-leap 16.0 | 1.104.1-bp160.1.1 | [OPENSUSE-SU-2026:22203-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22203-1.md) | Nov 7, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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