Unsynchronized Access to Shared Data in a Multithreaded Context Affecting github.com/moby/buildkit/frontend/gateway/forwarder package, versions <0.33.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMMOBYBUILDKITFRONTENDGATEWAYFORWARDER-20826441
- published11 Oct 2026
- disclosed5 Oct 2026
- credit2peopledesu
Introduced: 5 Oct 2026
NewCVE-2026-93319 Â (opens in a new tab)How to fix?
Upgrade github.com/moby/buildkit/frontend/gateway/forwarder to version 0.33.1 or higher.
Overview
Affected versions of this package are vulnerable to Unsynchronized Access to Shared Data in a Multithreaded Context through the container lifecycle handling in frontend/gateway/container/container.go and frontend/gateway/forwarder/forward.go. A malicious external BuildKit frontend can trigger a daemon panic by sending internal API requests that race container creation against discard/release operations. The race occurs when the gateway backend admits new containers while it is simultaneously cleaning up existing ones, allowing errgroup bookkeeping and container cleanup to run concurrently. An attacker can exploit this by driving repeated container-start and teardown requests through the internal gateway API, causing the BuildKit daemon to crash and interrupt builds.
Workarounds
- Avoid using external BuildKit frontends from untrusted sources; this prevents a malicious frontend from driving the internal API sequence that can trigger the daemon panic.
- Use Dockerfile builds instead of external BuildKit frontends when possible; the advisory states Dockerfile builds are unaffected, so this avoids the vulnerable gateway path.