CVE-2026-34926 is a CISA KEV-listed directory traversal in Trend Micro Apex One on-premise that allows a pre-authenticated local attacker to inject malicious code into the server’s key table, which the update mechanism then distributes to every managed endpoint in the deployment. Federal remediation deadline is June 4, 2026. Organizations running on-premise Apex One deployments face potential enterprise-wide endpoint fleet compromise from a single point of attack on the management server.