Microsoft has issued a critical security update for its Edge browser to address multiple vulnerabilities that could allow attackers to execute remote code on user systems. The vulnerabilities, identified as CVE-2025-21342, CVE-2025-21408, CVE-2025-21283, and CVE-2025-21279, were found in the latest version of Microsoft Edge, based on Chromium. These flaws share a common exploit scenario, where attackers can trigger remote code execution by luring users into clicking on specially crafted malicious links, which could be delivered through phishing emails or harmful websites.
Each vulnerability affects the browser’s renderer process, posing significant risks if exploited. CVE-2025-21342, the most concerning of the four, could lead to severe consequences, including the ability for attackers to view and alter sensitive information, crash browser tabs, and potentially gain control over the renderer process. However, Microsoft has categorized this flaw as “Exploitation Less Likely” at the time of publication. Similarly, CVE-2025-21408 and CVE-2025-21283 also allow remote code execution but have been assessed with a lower risk of exploitation.
The final vulnerability, CVE-2025-21279, presents a similar remote code execution threat triggered by user interaction with malicious links.
Although Microsoft has categorized all four vulnerabilities as having a lower likelihood of exploitation, the potential risks make updating the browser immediately essential. Microsoft has assured users that none of these vulnerabilities have been publicly disclosed or exploited in the wild as of the publication of the update, but given the nature of the vulnerabilities, it’s vital to stay protected by installing the latest security fixes.
To address the vulnerabilities, Microsoft released an updated version of Edge, 133.0.3065.51, on February 6, 2025. Users are strongly advised to check for updates by navigating to the Settings > About section of Edge. This update includes fixes that address the vulnerabilities and ensure improved security against these remote code execution risks. As a preventive measure, organizations should also encourage employees to update their browsers and remain vigilant against potential phishing attempts that could exploit these flaws.
