Miasma worm hits Microsoft GitHub; SolarWinds actively exploited; Chrome 429 patches

### Executive Summary This briefing details multiple high-severity, actively exploited threats — including a Miasma supply-chain worm compromising 73 Microsoft GitHub repositories, active SolarWinds Serv-U DoS exploitation, Chrome 149 and FFmpeg zero-days, UNC5221 APT backdoors targeting Microsoft 365, an Instagram takeover technique abusing Meta’s AI support bot, and a 2.6M-record DentaQuest data breach — and provides urgent mitigation actions such as patching, access audits, MFA enforcement, and monitoring.