CVE-2026-93319 in BuildKit
Summary
by MITRE • 10/05/2026
A malicious external BuildKit frontend can send requests using the internal API that can create conditions for a data race that can cause the BuildKit daemon to panic.
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Analysis
by VulDB Data Team • 10/05/2026
The vulnerability described involves a critical flaw within the Docker BuildKit component, specifically concerning its interaction with external build frontends and its internal application programming interface. BuildKit is designed as a next-generation toolchain for compiling containers, relying on a client-server architecture where various frontend implementations communicate with a central daemon to orchestrate image builds. The core issue arises when an untrusted or maliciously configured external BuildKit frontend attempts to interact directly with the internal API endpoints that are intended solely for trusted internal components. This unauthorized access vector allows the attacker to send specific, malformed requests that disrupt the normal synchronization mechanisms within the daemon process.
From a technical perspective, this flaw manifests as a data race condition within the concurrent execution environment of the BuildKit daemon. Modern container build tools utilize extensive concurrency to parallelize steps such as downloading base images, executing shell commands, and managing layer caches. When an external frontend sends requests via the internal API without proper authentication or validation checks, it can trigger simultaneous operations on shared resources that are not adequately protected by mutexes or other synchronization primitives. This lack of atomicity leads to a state where multiple threads attempt to read and write memory locations concurrently in an unpredictable manner. The resulting corruption of internal data structures causes the Go runtime, which powers BuildKit, to detect fatal inconsistencies and subsequently panic, leading to an immediate crash of the build daemon process.
The operational impact of this vulnerability is significant for environments relying on automated CI/CD pipelines or shared build infrastructure. A successful exploitation results in a denial of service against the BuildKit daemon, effectively halting all ongoing builds that depend on it. In continuous integration and deployment workflows, such interruptions can cause substantial delays in software delivery lifecycles. Furthermore, if the BuildKit daemon is running with elevated privileges to access host resources or Docker socket interactions, the crash could potentially be leveraged as part of a larger attack chain aimed at achieving privilege escalation or lateral movement within the container orchestration platform. The instability introduced by frequent panics also degrades the reliability and trustworthiness of the build environment for legitimate users.
This vulnerability aligns with CWE-362, which classifies concurrent execution using shared resources with improper synchronization as a software weakness. It is further contextualized within the MITRE ATT&CK framework under techniques related to resource hijacking or denial of service against infrastructure components. To mitigate this risk, organizations must ensure that their BuildKit deployments are configured to restrict access to internal APIs exclusively to trusted, authenticated clients. Implementing strict network policies and firewall rules can prevent external frontends from reaching these sensitive endpoints. Additionally, upgrading to patched versions of Docker Desktop and the standalone BuildKit daemon is essential, as vendors typically release updates addressing race conditions through improved synchronization logic and stricter input validation on API entry points. Security teams should also audit their CI/CD configurations to ensure that no untrusted build scripts or external services are granted access to internal build APIs.