Microsoft Warns of Two Actively Exploited Defender Vulnerabilities
Microsoft Warns of Two Actively Exploited Defender Vulnerabilities
https://thehackernews.com/2026/05/microsoft-warns-of-two-actively.html
Publish Date: 2026-05-21 06:55:00
Source Domain: thehackernews.com
Microsoft has disclosed that a privilege escalation and a denial-of-service flaw in Defender has come under active exploitation in the wild.
The former, tracked as CVE-2026-41091, is rated 7.8 on the CVSS scoring system. Successful exploitation of the flaw could allow an attacker to gain SYSTEM privileges.
“Improper link resolution before file access (‘link following’) in Microsoft Defender allows an authorized attacker to elevate privileges locally,” Microsoft said in an advisory.
The second vulnerability under exploitation is CVE-2026-45498 (CVSS score: 4.0), a denial-of-service bug impacting Defender. The two vulnerabilities have been addressed in Microsoft Defender Antimalware Platform versions 1.1.26040.8 and 4.18.26040.7, respectively.
The tech giant noted that systems that have disabled Microsoft Defender are not susceptible to the vulnerability, adding that no action is required to install the update since it automatically updates malware definitions and the Microsoft Malware Protection Engine for optimal protection.
Microsoft credited five different parties with discovering and reporting the flaw, including Sibusiso, Diffract, Andrew C. Dorman (aka ACD421), Damir Moldovanov, and an anonymous researcher.
To ensure the latest version of the Microsoft Malware Protection Platform and definition updates are being actively downloaded and installed, users are recommended to follow the steps below:
- Open the Windows Security program.
- In the navigation pane, select Virus & threat protection.
- Then click on Protection Updates in the Virus & threat protection section updates.
- Select Check for updates.
- In the navigation pane, select Settings, and then select About.
- Examine the Antimalware ClientVersion number.
There are currently no details on how the vulnerabilities are being exploited in the wild. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added both…
