Microsoft is publishing 167 vulnerabilities on April 2026 Patch Tuesday. Microsoft is aware of exploitation in the wild for one of today’s vulnerabilities, and public disclosure for one other. Microsoft evaluates 19 of the vulnerabilities published today as more likely to see future exploitation. So far this month, Microsoft has provided patches to address 80 browser vulnerabilities, which are not included in the Patch Tuesday count above.
Increasing volumes of vulnerabilities
Regular Patch Tuesday watchers will know that these vulnerability totals are significantly higher than usual, especially the browser numbers. Late last week, Microsoft published patches to resolve more than 60 browser vulnerabilities in a single day, which is a new record in that very specific category.
It might be tempting to imagine that this sudden spike was tied to the buzz around the announcement a week ago today of Project Glasswing, but this is not the case. Edge is based on the Chromium engine, and the Chromium maintainers acknowledge a wide range of researchers for the vulnerabilities which Microsoft republished last Friday. This reflects a significant industry-wide uptick in the volume of vulnerability reports over the past few weeks. A safe conclusion is that this increase in volume is driven by ever-expanding AI capabilities. We should expect to see further increases in vulnerability reporting volume as the impact of AI models extend further, both in terms of capability and availability.
SharePoint: zero-day spoofing
When everything is changing rapidly, it can be tempting to look to familiar things for comfort. SharePoint admins should start by addressing CVE-2026-32201, an exploited-in-the-wild spoofing vulnerability. The advisory doesn’t offer much detail, but does mention CWE-20: Improper Input Validation and low impact to confidentiality and integrity, with no impact to availability. Of course, the greatest attacker impact is typically achieved by chaining together multiple vulnerabilities that by themselves might not seem so bad.
Ever-increasing novel AI capabilities in offensive cybersecurity now appear to provide real competition for all but the most elite human researchers; if it was ever valid to suppose that a vulnerability with a CVSS v3 base score of 6.5 was unlikely to cause much pain, it’s certainly not a safe defensive assumption in 2026. Patches are available for all supported versions of SharePoint, including SharePoint 2016, which moves beyond extended support on July 14, 2026.
Defender: zero-day elevation of privilege
Microsoft Defender receives a patch today for CVE-2026-33825, a local privilege escalation vulnerability for which Microsoft is aware of public disclosure. Successful exploitation leads to SYSTEM privileges, so this is certainly worth patching sooner rather than later. Microsoft points out that no action should be required to install this update, since the Microsoft Defender Antimalware Platform automatically updates by default. A further silver lining is that systems that have disabled Microsoft Defender are not in an exploitable state. Hopefully, any such system is running a suitable third-party replacement for Defender’s capabilities.
Windows [I don’t like] IKE: zero-day pre-auth RCE
The Windows Internet Key Exchange (IKE) Services Extensions is the site of CVE-2026-33824, a critical unauthenticated remote code execution vulnerability. Exploitation requires an attacker to send specially crafted packets to a Windows machine with IKE v2 enabled, which could enable remote code execution. Vulnerabilities leading to unauthenticated RCE against modern Windows assets are relatively rare, or we’d see more wormable vulnerabilities self-propagating across the internet. However, since IKE provides secure tunnel negotiation services, for instance for VPNs, it is necessarily exposed to untrusted networks and reachable in a pre-authorization context. It’s hard to imagine this turning into a rampaging internet-wide worm, but there’s plenty of scope for initial access abuse, so this IKE vulnerability is still yikes.
The advisory does contain a section with potential mitigations for anyone unable to patch immediately, which center on least-privilege restriction of relevant UDP traffic. This same portion of the advisory also furnishes a helpful link to the definition of the word “mitigations” in the MSDN glossary. All versions of Windows back as far as Server 2016 and Windows 10 1607 LTSC receive patches.
The advisory credits both the WARP and MORSE (Microsoft Offensive Research & Security Engineering) teams at Microsoft. MORSE appears in Acknowledgements over the past few years, but today marks the first explicit mention of WARP in a Microsoft security advisory Acknowledgements section; we can speculate that WARP is an internal designator for the Microsoft Windows Enterprise Security Team.
Microsoft lifecycle update
In Microsoft lifecycle news, extended support ends April 14, 2026 for a wide range of Microsoft product legacy enterprise tools, including Dynamics C5 2016, Dynamics NAV 2016, App-V 5.0 and App-V 5.1, UE-V 2.1, and BitLocker Administration and Monitoring 2.5 SP1. Microsoft .NET 9 STS (Standard Term Support, as distinct from Long Term Support) was originally scheduled to move past the end of support in May 2026, but late last year, Microsoft granted a six-month extension, so that .NET 9 STS now reaches end of support on November 10, 2026.
