CVE-2026-93321 Malformed LLB file operation can crash buildkitd
A malicious frontend can submit a malformed LLB definition to crash the BuildKit daemon, disrupting all active builds.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93321?
CVE-2026-93321 is a medium-severity denial of service vulnerability in moby BuildKit, published on 5 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A malicious frontend can submit an LLB definition that causes buildkitd to panic and terminate, interrupting all builds running on that daemon.
Weakness: CWE-129
Which versions are affected by CVE-2026-93321?
How do I fix CVE-2026-93321?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-93321 being exploited?
There is no known exploitation of CVE-2026-93321 in the wild and no public exploit code.
Sources
Also known as AZL-106821, BELL-CVE-2026-93321, GHSA-fjj4-h6vf-m9hj, UBUNTU-CVE-2026-93321.