ThreatsDay Bulletin: AI Prompt RCE, Claude 0-Click, RenEngine Loader, Auto 0-Days & 25+ Stories

This week's threat bulletin highlights attackers increasingly relying on trusted tools and overlooked vulnerabilities rather than novel exploits, with a shift toward quieter, longer-term access over disruptive attacks. Key incidents include a command injection flaw (CVE-2026-20841, a severity rating of 8.8 out of 10) in Windows Notepad that allows remote code execution through malicious Markdown links, over 510 advanced persistent threat operations (coordinated cyberattacks by nation-states or organized groups) targeting 67 countries with 173 focused on Taiwan, and two new information stealers (LTX Stealer and Marco Stealer) harvesting credentials and sensitive data from Windows systems.