Microsoft · Defender
CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
Exploited in attacks
Medium 4.0 Attack chance: 63%
What it is
Microsoft Defender Denial of Service Vulnerability
CISA: Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Deadline for US federal agencies: June 3, 2026
More exploited flaws from Microsoft
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| May 20, 2026 | Link Following | Defender | High 7.8 | 8.2% |
| Apr 22, 2026 | Insufficient Granularity of Access Control | Defender | High 7.8 | 6.7% |
| Dec 13, 2022 | SmartScreen Security Feature Bypass | Defender | Medium 5.4 | 76% |
| Nov 3, 2021 | Remote Code Execution | Defender | High 7.8 | 40% |
| Oct 13, 2026 | Command Injection | Windows | High 8.8 | 9.8% |
| Sep 25, 2026 | Code Injection | SharePoint | High 8.8 | 8.2% |
| Sep 8, 2026 | Link Following | Windows | High 7.8 | 0.4% |
| Sep 8, 2026 | Heap-Based Buffer Overflow | Windows | High 7.8 | 0.4% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.