Microsoft has released its biggest patch month of the year to-date. This update addresses 59 vulnerabilities, including six that are actively exploited in the wild. This update, which includes critical patches for various products, aims to protect users from potential threats that could compromise their systems. The 14 vulnerabilities are of varying severity, including high Common Vulnerability Scoring System (CVSS) scores, reflecting their serious nature.
The big one is CVE-2026-21513. Its severity rating is 8.8 on the CVSS scale due to an important security protection mechanism failure of the MSHTML Framework. This vulnerability enables remote, non-authenticated adversaries to circumvent security mechanisms over the network. A second major vulnerability has appeared as well: CVE-2026-21514, with the same CVSS score of 7.8. This vulnerability permits adversaries to take advantage of unsanitized inputs to Microsoft Office Word, even letting them circumvent local security protections. CVE-2026-21519 also has a high severity score of 7.8. This bug is a type confusion vulnerability in the Desktop Window Manager and lets an attacker with valid credentials perform a local privilege escalation.
Overview of Key Vulnerabilities
CVE-2026-21513 is the most severe of several addressed. Severity This vulnerability represents a major flaw in the Microsoft MSHTML Framework’s defense-in-depth protection layer. This abstraction is fundamental to presenting DOM-based HTML content in many Windows apps.
“CVE-2026-21513 is a security feature bypass vulnerability in the Microsoft MSHTML Framework, a core component used by Windows and multiple applications to render HTML content,” – Jack Bicer, director of vulnerability research at Action1.
The implications of this flaw are severe. Specifically, it allows specially-formatted files to skip Windows security warnings, which could lead to deadly actions being executed with as little as a single mouse click. This would leave users open to unintended execution of malicious content without any notice to them.
A zero-day vulnerability, CVE-2026-21514, endangers all versions of Microsoft Office Word. It opens the software to attacks since it bases its security decisions on untrusted inputs. Attackers can take advantage of this vulnerability to go around local security features, greatly raising the risk of unauthorized access to sensitive data.
Active Exploits and Additional Vulnerabilities
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has identified six of these vulnerabilities in its Known Exploited Vulnerabilities (KEV) catalog. These vulnerabilities are a real and present danger to users, making clear that they require swift action. CVE-2026-21525 CVSS Score: 6.2 It is a null pointer dereference in the Windows Remote Access Connection Manager. This vulnerability is connected to a zero-day exploit and emphasizes the critical importance for users to keep their systems up to date.
CVE-2026-21519 is an access control problem due to a type confusion in Desktop Window Manager. An authorized, local attacker can exploit this vulnerability to elevate their privileges. This is a recipe for disaster if abused.
“These [CVE-2026-21519 and CVE-2026-21533] are local privilege escalation vulnerabilities, which means an attacker must have already gained access to a vulnerable host,” – Kev Breen, senior director of cyber threat research at Immersive.
Once an attacker is in the system, they can take advantage of the privilege escalation vulnerabilities themselves. This provides them a pathway for SYSTEM-level access. With such elevated privileges, they could disable security tools, deploy malware, or access sensitive credentials that could lead to further breaches.
Importance of Timely Updates
The impact of this security update release underscores the role that timely software updates play in keeping our nation’s cybersecurity infrastructure safe and secure. Microsoft strongly urges all users to immediately and without delay stop these vulnerabilities to prevent potential risks from being exploited.
“These prompts are designed to be clear and actionable, and you’ll always have the ability to review and change your choices later,” – Logan Iyer, Distinguished Engineer at Microsoft.
With these vulnerabilities in mind, users need to be vigilant in looking for updates to their systems. To stay secure, apply patches as soon as they are released. Not doing so would put them at risk of being exposed to exploits that leverage these vulnerabilities.