CVE-2024-21351: in the CISA KEV catalogue
Microsoft Windows SmartScreen Security Feature Bypass Vulnerability. CISA added CVE-2024-21351 to the Known Exploited Vulnerabilities catalogue on 2024-02-13 with a default due date of 2024-03-05. Known ransomware campaign use: Unknown. Forensic triage flag: No.
Microsoft Windows SmartScreen contains a security feature bypass vulnerability that allows an attacker to bypass the SmartScreen user experience and inject code to potentially gain code execution, which could lead to some data exposure, lack of system availability, or both. (CISA description)
- Vendor / product
- Microsoft Windows
- CWE
- CWE-94
- CISA required action
- Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- EPSS
- 28%, percentile 98 (scored 2026-11-03)
EPSS puts about 28 in 100 odds (28%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 98% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2024-21351 in the CISA KEV catalogue?
Yes. CISA added CVE-2024-21351 (Microsoft Windows SmartScreen Security Feature Bypass Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2024-02-13. CISA's default due date for it is 2024-03-05.
Is CVE-2024-21351 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2024-21351. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2024-21351?
CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2024-21351