Weekly Cybersecurity Newsletter Bulletin – Cisco and Android 0-Day, BragJack Attack, Claude Opus 5 Used to Hack OpenAI, and 20+ Stories

This week’s roundup covers a maximum-severity Cisco ISE zero-day under active exploitation, an actively exploited Android modem flaw on Pixel devices, a browser-extension attack that hijacks AI agents across five browsers, and researchers using Claude Opus 5 to compromise OpenAI’s forum and reach its internal source code. Also inside: a WordPress one-click RCE chain, an unpatched Steam privilege-escalation zero-day, a Microsoft 365 phishing kit that beats MFA in 78 seconds, Apple’s 273-vulnerability patch marathon, and more. Cisco issued an urgent advisory for CVE-2026-76460, a maximum-severity (CVSS 10.0) authentication-bypass flaw in Cisco Identity Services Engine (ISE) and ISE-PIC that is already being actively exploited. The bug stems from insufficient authentication controls on an API endpoint, letting an unauthenticated remote attacker bypass the management interface and gain command execution with root privileges — a foothold that can be used to alter configurations, steal credentials, and pivot laterally across enterprise networks. No workaround exists, so Cisco is pushing immediate patches: ISE 3.1 Patch 12, 3.2 Patch 11, 3.3 Patch 12, 3.4 Patch 7, and 3.5 Patch 4. Cisco ISE 3.0, which has reached end of maintenance, remains exposed and should be migrated off. Administrators unable to patch immediately are advised to restrict management…