BuildKit EUVD-2026-92539

Requires a victim to build an attacker-controlled Dockerfile or build context in which special file inodes (device nodes, FIFOs, or sockets) are substituted where BuildKit expects regular files, triggering CWE-441 confused-deputy file actions. The high-impact outcome - unintended host device access - is LIMITED to rootful BuildKit workers; rootless configurations face primarily operation-blocking (availability) effects. Key limiting factors: the attack is local (AV:L) via build input rather than remote, and it needs the victim to actually run a build on the malicious input (UI:A), so it is most relevant to multi-tenant or untrusted-source CI/CD pipelines using rootful workers.

This is a medium-severity, defense-in-depth style flaw rather than an urgent remote-exploitation priority. The vendor-supplied CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:A) scores 6.0 and makes the real constraint clear: exploitation is LOCAL and requires active user interaction (UI:A) - specifically, a victim must initiate a BuildKit build against attacker-supplied input. There is no EPSS score, no CISA KEV listing, and no public POC provided in the intelligence, so exploitation status is 'no public exploit identified at time of analysis.' Impact is split: the vulnerable-system metrics are modest (VI:L/VA:L) while the subsequent-system metrics are high (SI:H/SA:H), which is consistent with the description's warning that on ROOTFUL workers the confused-deputy behavior (CWE-441) can reach host devices beyond the build sandbox - a genuine sandbox-escape concern in multi-tenant CI/CD. Note one conflict to verify: the 'Information Disclosure' tag and the 'host device access' language imply confidentiality impact, yet the CVSS vector sets VC:N - the modeled impact is integrity/availability, not disclosure. Overall: real but conditional risk, prioritize where untrusted Dockerfiles/build contexts are built on rootful BuildKit workers.

In a shared CI/CD pipeline, an attacker submits a repository containing a crafted build context in which special file inodes (e.g., device, FIFO, or socket nodes) are placed where BuildKit expects regular files. When the pipeline's rootful BuildKit worker processes the build, the file operations are performed against those special files, allowing unintended access to host devices or blocking of build operations. No public exploit code was identified in the provided intelligence.