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