Daily Security Briefing #253

May 13, 2026 | Read Online

Critical Patch Tuesday, Ransomware Gang Hacked, and AI-powered vulnerability discovery…

Executive Summary

Patch Tuesday brought a massive wave of vulnerabilities from Microsoft, with 137 critical issues addressed. Meanwhile, the Gentlemen RaaS has been hacked, exposing their internal structure and operations. Additionally, Microsoft’s new AI system, MDASH, has already discovered 16 Windows flaws fixed in Patch Tuesday.

Top Articles

Patch Tuesday - May 2026 Microsoft published 137 vulnerabilities on May 2026 Patch Tuesday, with no public disclosure or exploitation in the wild. The update includes critical RCE for Windows Netlogon (CVE-2026-41089). Rapid7

When IT Support Calls: Dissecting a ModeloRAT Campaign from Teams to Domain Compromise Attackers use trusted tools like Microsoft Teams to convince employees to open the door. A recent incident escalated into full compromise, involving malware deployment and credential theft. Rapid7

When the Ransomware Gang Gets Hacked: What the Gentlemen Leak Reveals About Modern Ransomware Risk The Gentlemen RaaS has 400+ public victims and is the #2 most active ransomware group globally in 2026. Their internal systems were breached, exposing their operational structure. Checkpoint

Microsoft Teams Vulnerability Allows Hackers to Perform Spoofing Attacks A newly discovered security flaw in Microsoft Teams for Android could allow attackers to trick users and compromise sensitive corporate information. An official security update has been issued. GBHackers

Microsoft Releases Cumulative Update for Windows 11, Version 25H2 and 24H2 Microsoft’s May 2026 Patch Tuesday updates deliver critical security fixes and system improvements for multiple Windows 11 versions. The deployment includes cumulative update KB5089549. GBHackers

Foxconn Attack Highlights Manufacturing’s Cyber Crisis A Nitrogen ransomware attack on Foxconn’s North American facilities is one of 600 hits on manufacturers this year, as gangs increasingly target the sector for its low tolerance for downtime. DarkReading

Microsoft’s MDASH AI System Finds 16 Windows Flaws Fixed in Patch Tuesday Microsoft unveiled a new multi-model artificial intelligence (AI)-driven system called MDASH to facilitate vulnerability discovery and remediation at scale. TheHackerNews

Azerbaijani Energy Firm Hit by Repeated Microsoft Exchange Exploitation A threat actor with affiliations to China has been linked to a “multi-wave intrusion” targeting an unnamed Azerbaijani oil and gas company. TheHackerNews

Critical Fortinet FortiSandbox Flaw Enables Remote Code Execution A severe missing authorization vulnerability could allow completely unauthenticated hackers to take over vulnerable systems and execute malicious code from afar. CyberPress

New critical Exim mailer flaw allows remote code execution A critical vulnerability affecting certain configurations of the Exim open-source mail transfer agent could be exploited by an unauthenticated remote attacker to execute arbitrary code. BleepingComputer

AI Transparency: This newsletter uses AI to curate, rank, and summarize cybersecurity content from leading industry blogs. All articles link directly to original authors. Executive summaries are AI-generated based on article content. I curate the sources and deliver the digest—the original authors deserve the credit for their excellent work.