# CVE-2026-121522: Moby BuildKit Git source resolver panic

Source: https://junglewise.ai/threats/cve-2026-121522-in-buildkit-versions-v0-26-0-through-v0-34-1-a-specific-build  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-03. Updated: 2026-11-03  
License: CC BY 4.0 with a link back

CVE-2026-121522 · Severity: info · Published 2026-11-03

BuildKit is a container build engine used to compile Docker images and other container artifacts. A crafted build definition that references the same Git source twice can cause the BuildKit daemon to crash, interrupting all ongoing builds on that system. The issue affects versions v0.26.0 through v0.34.1.

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

## Quick answers

**Is CVE-2026-121522 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121522 being exploited in the wild.

**How severe is CVE-2026-121522?** Informational severity, published 3 November 2026.

**Which products and versions are affected?** Moby BuildKit v0.26.0 through v0.34.1.

**Is there a fix for CVE-2026-121522?** Yes: fixed in v0.34.2. Until then: Avoid using untrusted build definitions. Only very specific builds using Git dependencies are affected; restrict who can submit build definitions to BuildKit. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-121522 attacked?** It is attacked over the network or from the adjacent network or with local access.

**Am I affected by CVE-2026-121522?** 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 v0.34.2

Avoid using untrusted build definitions. Only very specific builds using Git dependencies are affected; restrict who can submit build definitions to BuildKit.

## Technical details

The vulnerability is a denial-of-service via daemon panic in BuildKit's Git source resolver when a build definition resolves metadata for the same Git reference twice, triggering an unhandled panic condition. The attack requires the ability to submit or control a build definition (either via untrusted Dockerfile or direct BuildKit API access). A fix is available in v0.34.2.

## Affected products

- Moby BuildKit v0.26.0 through v0.34.1

## Timeline

- 2026-11-03: disclosed

## References

- [https://github.com/moby/buildkit/security/advisories/GHSA-2fqp-xg6f-v7gj](https://github.com/moby/buildkit/security/advisories/GHSA-2fqp-xg6f-v7gj)

## Related threats

- [Moby BuildKit arbitrary extended attribute setting](https://junglewise.ai/threats/cve-2026-121520-in-buildkit-versions-prior-to-v0-34-1-a-malicious-client-with)
- [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)
- [Moby buildkit Dockerfile memory exhaustion via oversized files](https://junglewise.ai/threats/cve-2026-93323-the-dockerfile-frontend-loaded-the-dockerfile-and-dockerignore)