Database/Container, Kubernetes & orchestration

BuildKit: malicious frontend can crash buildkitd with a crafted LLB definition, killing all builds

CVSS 6.9CVE-2026-93321Container, Kubernetes & orchestration+1 more CVEscurated

Impact

A caller that can submit a build to buildkitd can send an LLB (low-level build) definition that panics the daemon. The daemon process terminates, so every concurrent build on that instance dies with it, including unrelated tenants' builds and the cache state in flight. On a GPU fleet this matters where buildkitd is the shared image-build backend for CI that produces CUDA/inference images: one tenant's build request stalls the pipeline that feeds node rollouts and model-server deploys. No data disclosure or code execution is claimed - this is availability only. The vendor split this across two ids (CVE-2026-93321 and CVE-2026-93322) with identical descriptions, scores, advisories and fix release; they are recorded here as one issue.

Who can reach it

Local caller able to submit a build to the buildkitd daemon - in practice any CI job, user or frontend with access to the build endpoint. The CVSS vector is AV:L/PR:N, so no authentication beyond reaching the daemon socket is required.

What to do

Upgrade BuildKit to v0.33.1 and restart buildkitd. In-flight builds are lost on restart, so schedule it between pipeline runs; no node reboot or firmware work is involved. Until then, restrict who can submit builds to the shared daemon and avoid exposing buildkitd to untrusted frontends.

Also covers 1 CVE

The vendor assigned a separate id to each affected code path. They share this advisory, this score and this fix, so they are one entry here.

CVE-2026-93322

References

https://nvd.nist.gov/vuln/detail/CVE-2026-93321 https://github.com/moby/buildkit/releases/tag/v0.33.1 https://github.com/moby/buildkit/security/advisories/GHSA-fjj4-h6vf-m9hj https://github.com/moby/buildkit/security/advisories/GHSA-cv6p-7w7g-xjwq

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.