Critical RCEs: Microsoft Defender, Linux kernel, Cisco Workload; Showboat targets telcos

A high-severity briefing reports active exploitation of multiple critical vulnerabilities and targeted malware campaigns: Microsoft Defender privilege escalation (CVE-2026-41091) is being exploited in the wild, a long-standing Linux kernel flaw allows local root access, Cisco Secure Workload received an RCE patch, and Chinese-aligned APTs are using Showboat and JFMBackdoor against telcos; immediate patching, monitoring, and incident response are recommended.