CVE-2026-33748
BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner.
Impact
BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. Prior to version 0.28.1, insufficient validation of Git URL fragment subdir components may allow access to files outside the checked-out Git repository root. Possible access is limited to files on the same mounted filesystem. The issue has been fixed in version v0.28.1 The issue affects only builds that use Git URLs with a subpath component. As a workaround, avoid building Dockerfiles from untrusted sources or using the subdir component from an untrusted Git repository where the subdir component could point to a symlink.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/moby/buildkit | < 0.28.1 | 0.28.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Mobyproject | Buildkit | before 0.28.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://docs.docker.com/build/concepts/context/#url-fragments
- https://github.com/moby/buildkit/releases/tag/v0.28.1
- https://github.com/moby/buildkit/security/advisories/GHSA-4vrq-3vrq-g6gg
- https://github.com/advisories/GHSA-4vrq-3vrq-g6gg
- https://nvd.nist.gov/vuln/detail/CVE-2026-33748