Docker BuildKit EUVD-2026-46311

The attacker must be a BuildKit client or frontend with at least low-privilege access (PR:L per CVSS 4.0) to a running buildkitd instance - this typically means possession of valid credentials or a Unix socket connection that grants client-level access to the daemon. The attack requires conditions to be present (AT:P), meaning the daemon must be configured to accept connections from the attacker's client, which is the normal operational mode for shared build infrastructure but may not apply to strictly isolated single-tenant deployments. Exploitation is limited by: (1) the attacker must be a legitimate or compromised client/frontend, not an anonymous network actor; (2) the impact is limited to availability - no code execution or data exfiltration is possible via this path; (3) the crash affects only the BuildKit daemon process, not the host OS or other containers. There is no indication that default-locked or socket-only deployments (where client access is physically restricted) are at meaningful risk without prior compromise of a connected system.

The CVSS 4.0 score of 6.3 reflects a network-reachable, low-complexity availability-only impact with low privileges required (PR:L) and attack requirements present (AT:P). The availability impact is rated High (VA:H) with no confidentiality or integrity impact, which is consistent with the crash-only nature of a Go panic. EPSS data was not provided, limiting probabilistic exploitation estimation. The vulnerability is not listed in the CISA KEV catalog and no public exploit code has been identified, suggesting this is a lower-priority issue absent of threat actor targeting. However, in automated CI/CD and multi-tenant build environments where BuildKit daemons serve numerous clients, a crash can cascade into build pipeline failures affecting multiple teams. The AT:P qualifier (attack requirements present) tempers the risk - not every BuildKit deployment is trivially reachable by an adversarial client, but shared build infrastructure or externally-accessible daemons are realistic targets. Overall: moderate real-world risk in CI/CD-heavy organizations, lower risk in isolated single-tenant environments.

An attacker controlling a build frontend or a compromised CI pipeline step with access to a shared BuildKit daemon sends a deliberately malformed gRPC request - for example, a crafted Solve or Stat request with unexpected field values - that bypasses input validation and triggers an unrecovered Go panic in buildkitd, crashing the daemon and interrupting all active and queued build jobs for all users of that daemon. No public proof-of-concept code has been identified at time of analysis, though the network-accessible and low-complexity nature of the attack (AV:N/AC:L) suggests that exploit development would be straightforward once the triggering request structure is identified.