Microsoft's Patch Tuesday 2025: A Year in Review
Microsoft's Patch Tuesday, a monthly software patch release, has been a cornerstone of cybersecurity for over two decades. In 2025, it addressed a staggering 1,130 CVEs, a 12% increase from 2024. This marks the second consecutive year with over 1,000 CVEs addressed, and the third time since Patch Tuesday's inception. Here's a breakdown of the key findings and insights from this year's Patch Tuesday releases.
Elevated Vulnerability Counts
- Zero-Day Vulnerabilities: Microsoft patched 41 zero-day vulnerabilities in 2025, with 24 exploited in the wild. This highlights the ongoing challenge of staying ahead of threat actors who exploit these vulnerabilities before patches are available.
- Exploitation Activity: EoP vulnerabilities (Elevation of Privilege) dominated, accounting for 38.3% of all vulnerabilities. RCE (Remote Code Execution) followed at 30.8%, while information disclosure flaws made up 14.2%.
Severity and Impact Analysis
Microsoft categorizes vulnerabilities into four severity levels: Low, Moderate, Important, and Critical. In 2025, 91.3% of CVEs were rated Important, followed by Critical at 8.1%. Moderate vulnerabilities were rare, accounting for only 0.4%.
The impact categories further break down vulnerabilities into specific threats: RCE, EoP, DoS, information disclosure, spoofing, security feature bypass, and tampering. EoP vulnerabilities, often exploited by advanced persistent threats (APTs), dominated with 38.3%. RCE vulnerabilities, while less prevalent, still posed a significant risk at 30.8%.
Notable Zero-Day Exploits
Several zero-day vulnerabilities were exploited in 2025, showcasing the real-world impact of these vulnerabilities:
- CVE-2025-24983: Exploited by the PipeMagic backdoor to spread ransomware, this EoP vulnerability targeted the Windows Win32 Kernel Subsystem.
- CVE-2025-29824: Abused by the PipeMagic backdoor to deploy RansomEXX ransomware, this EoP vulnerability affected the Windows Common Log File System Driver.
- CVE-2025-26633: Exploited by the MSC EvilTwin trojan loader and associated malware, this security feature bypass vulnerability targeted Microsoft Management Console.
- CVE-2025-33053: Used by the Stealth Falcon APT to deploy Horus Agent malware, this RCE vulnerability targeted Internet Shortcut Files.
- CVE-2025-49704 and CVE-2025-49706: Chained together in the ToolShell attack, these vulnerabilities were exploited by multiple APTs and nation-state actors to deploy malware and ransomware.
Looking Ahead
The upward trend in vulnerability counts highlights the ongoing challenge of cybersecurity. As Microsoft continues to address vulnerabilities, defenders must stay vigilant and promptly apply patches to mitigate risks. Attackers are constantly evolving, seeking new ways to exploit vulnerabilities. The Tenable Research Special Operations (RSO) team will continue to provide in-depth analysis and actionable insights through their monthly Patch Tuesday blogs, empowering organizations to strengthen their security posture.
