Contrast EUVD-2026-87850

Exploitation requires a malicious process running on the untrusted Kubernetes host with the ability to open a connection to the confidential workload's Kata agent over the VSOCK channel; it targets the Kata agent policies GENERATED BY THE CONTRAST CLI in versions before 1.19.1. This is not remotely reachable over a standard network (AV:A, Adjacent) - the attacker must already have host-level foothold, which is precisely the untrusted-host adversary Contrast's confidential-computing model assumes. No authentication or user interaction is needed (PR:N/UI:N). Deployments already upgraded to 1.19.1, or those applying the published rego policy fix via 'contrast generate --policy', are not affected.

The vendor (via VulnCheck) rates this CVSS 4.0 8.6 (High) with vector AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N, and I broadly agree on the impact profile: this is a genuine confidentiality-and-integrity break, not a high-CVSS-but-low-risk paper cut. The critical framing is the confidential-computing threat model - Contrast explicitly treats the Kubernetes host/cluster-admin as an UNTRUSTED adversary, so the 'PR:N / attacker on the host with VSOCK access' precondition is exactly the boundary the product exists to defend, meaning a bypass defeats the core security guarantee. That said, the attack vector is Adjacent (AV:A), not Network: the attacker must already have a malicious process on the untrusted host able to reach the Kata agent VSOCK, which is a meaningful gate outside the confidential-computing model. Exploitation signals are thin: no EPSS score, not in CISA KEV, and no public POC identified at time of analysis - a rego-only workaround is published but that is a mitigation, not exploit code. Note the vendor set VA:N (no availability impact) despite describing 'full guest takeover'; that is defensible since the vulnerability yields arbitrary file writes and data disclosure rather than a direct crash, but full takeover could cascade to availability in practice. The 'Information Disclosure' tag understates the issue - CWE-59 (link following) enabling arbitrary writes to overwrite security-critical files makes INTEGRITY the primary impact.

An attacker who has compromised the untrusted Kubernetes host (the exact adversary Contrast is designed to defend against) connects to the confidential workload's Kata agent over VSOCK and issues a crafted series of CopyFile requests. Exploiting the flawed CopyFile symlink verification (CWE-59), the writes are redirected via symlinks to overwrite security-critical files in the guest root filesystem or to coerce the workload into disclosing sensitive data, resulting in full guest takeover. No public exploit code is identified at time of analysis, though a rego-only fix published in the advisory reveals the exact mechanism.