Quick answers
- Is CVE-2026-121542 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-121542 being exploited in the wild.
- How severe is CVE-2026-121542?
- Informational severity, published 3 November 2026.
- Which products and versions are affected?
- Docker Buildx v0.19.0 through v0.38.0.
- Is there a fix for CVE-2026-121542?
- Yes: fixed in Buildx v0.38.1. Until then: Run only trusted Bake definitions until upgrading. Verify that Bake definitions do not contain suspicious paths outside of trusted directories, and ensure no matching filenames exist alongside the project directory that could trigger the bypass condition. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-121542 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-121542?
- Check whether you run Docker Buildx at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: Buildx v0.38.1
Run only trusted Bake definitions until upgrading. Verify that Bake definitions do not contain suspicious paths outside of trusted directories, and ensure no matching filenames exist alongside the project directory that could trigger the bypass condition.
Technical details
The vulnerability is a filesystem entitlement check bypass in Docker Buildx's Bake definition processor. Paths under the same parent directory as the current working directory, whose names use the working directory's basename as a prefix, can skip the fs.read approval check. Exploitation requires both an untrusted Bake definition and specific matching filenames to exist alongside the project directory; the issue is fixed in v0.38.1.
Affected products
- Docker Buildx v0.19.0 through v0.38.0
Timeline
- 2026-11-03: disclosed
- 2026-11-03: patched