Microsoft Defender known exploited vulnerabilities
We track 5 CVEs in Microsoft Defender. All of them are on CISA's Known Exploited Vulnerabilities catalog, meaning CISA has evidence of exploitation in the wild (listed 2021–2026). CISA flags 2 of them as used in ransomware campaigns. The most recent is CVE-2026-45498, added to KEV on .
Also listed as: Defender Antimalware Platform. CISA, NVD and vendor advisories name the same product differently; each CVE page keeps the wording from its source.
- CVEs tracked
- 5
- On CISA KEV
- 5
- Ransomware use
- 2
- Rated critical
- 0
Every Microsoft Defender CVE we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV | Patch by |
|---|---|---|---|---|---|
| CVE-2026-45498 Microsoft Defender Denial of Service Vulnerability | [ MEDIUM ] | 4.0 | 1.3% | ||
| CVE-2026-41091 Microsoft Defender Link Following Vulnerability | [ HIGH ] | 7.8 | 0.4% | ||
| CVE-2026-33825 Microsoft Defender Antimalware Platform Local Privilege Escalation (BlueHammer)ransomware usewrite-up | [ HIGH ] | 7.8 | 0.4% | ||
| CVE-2022-44698 Microsoft Defender SmartScreen Security Feature Bypass Vulnerabilityransomware use | [ MEDIUM ] | 5.4 | 76.3% | ||
| CVE-2021-1647 Microsoft Defender Remote Code Execution Vulnerability | [ HIGH ] | 7.8 | 39.7% |
Sorted by date added to KEV. Severity and CVSS as stated by NVD or the vendor; EPSS from FIRST.org. "Patch by" is CISA's BOD 22-01 deadline for US federal agencies, a useful priority signal for everyone else. Machine-readable: /api/v1/vendors/microsoft.json.
Our Microsoft Defender coverage
Other Microsoft products
Every row links to its CVE record with the CISA required action, catalog coverage and primary sources. We describe impact and remediation only; no exploit code. See the full KEV tracker or compare KEV catalogs.