# CVE-2026-93320: Moby BuildKit improper handling of special files in snapshots

Source: https://junglewise.ai/threats/cve-2026-93320-buildkit-may-be-tricked-into-performing-file-actions-with-special  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-05. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-93320 · Severity: info · Published 2026-10-05

BuildKit, a container image build toolkit, may be tricked into treating special files (such as device files) as regular files in build snapshots. An attacker can exploit this to block build operations or, on rootful worker configurations, gain unintended access to host devices. Rootless mode mitigates device access but does not prevent denial-of-service attacks.

Technologies: [Moby BuildKit](https://junglewise.ai/threats/technologies/moby-buildkit). Vendors: [Moby](https://junglewise.ai/threats/vendors/moby).

## Quick answers

**Is CVE-2026-93320 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-93320 being exploited in the wild.

**How severe is CVE-2026-93320?** Informational severity, published 5 October 2026.

**Which products and versions are affected?** Moby BuildKit <=v0.33.0.

**Is there a fix for CVE-2026-93320?** Yes: fixed in v0.33.1. Until then: Avoid running untrusted builds. For rootful worker deployments, consider switching to rootless mode to mitigate device access, though this does not prevent denial-of-service attacks from special files. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-93320 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-93320?** Check whether you run Moby BuildKit 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 v0.33.1

Avoid running untrusted builds. For rootful worker deployments, consider switching to rootless mode to mitigate device access, though this does not prevent denial-of-service attacks from special files.

## Technical details

BuildKit improperly validates file types when performing file operations in build snapshots, allowing special file inodes to be used where regular files are expected. The vulnerability affects snapshot reads and LLB mkfile operations. Local attack vector with user interaction required; on rootful workers, this permits unintended host device access; rootless workers are protected from device access but remain vulnerable to operations being blocked.

## Affected products

- Moby BuildKit <=v0.33.0

## Timeline

- 2026-09-30: disclosed
- 2026-09-30: patched

## References

- [https://github.com/moby/buildkit/releases/tag/v0.33.1](https://github.com/moby/buildkit/releases/tag/v0.33.1)
- [https://github.com/moby/buildkit/security/advisories/GHSA-9728-qjrv-2xh2](https://github.com/moby/buildkit/security/advisories/GHSA-9728-qjrv-2xh2)

## Related threats

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- [Moby BuildKit malformed LLB merge operation denial of service](https://junglewise.ai/threats/cve-2026-93321-a-malicious-frontend-can-submit-an-llb-definition-that-causes)
- [Moby BuildKit proxy CA cleanup disruption](https://junglewise.ai/threats/cve-2026-93315-when-proxy-networking-with-ca-injection-is-enabled-a-build-can)
- [Moby BuildKit Git source policy validation bypass](https://junglewise.ai/threats/cve-2026-93326-a-build-step-for-a-git-source-crafted-in-a-specific-way-can)