Security Digest · Vulnerability record · Known exploited
CVE-2024-21351: Microsoft Windows SmartScreen Security Feature Bypass Vulnerability
Exploited in the wild (CISA KEV). Windows SmartScreen Security Feature Bypass Vulnerability
CISA KEV · added 2024-02-13 CVSS 7.6 High EPSS 27.8% · p98
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run Microsoft Windows. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-02-13, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-03-05; treat that as the outer limit, not the target.
- EPSS 27.8%, percentile 98: FIRST’s model estimates a 27.8% chance of exploitation activity in the next 30 days, higher than 98% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
What it is
Windows SmartScreen Security Feature Bypass Vulnerability
CISA’s summary
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.
Weakness type: CWE-94.
Product: Microsoft Windows · Assigned by: microsoft · Published: 2024-02-13
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Microsoft | Windows 10 Version 1507 | 10.0.10240.0 < 10.0.10240.20469 |
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 < 10.0.14393.6709 |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 < 10.0.17763.5458 |
| Microsoft | Windows 10 Version 1809 | 10.0.0 < 10.0.17763.5458 |
| Microsoft | Windows 10 Version 21H2 | 10.0.19043.0 < 10.0.19044.4046 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 < 10.0.19045.4046 |
| Microsoft | Windows 11 version 21H2 | 10.0.0 < 10.0.22000.2777 |
| Microsoft | Windows 11 version 22H2 | 10.0.22621.0 < 10.0.22621.3155 |
| Microsoft | Windows 11 version 22H3 | 10.0.22631.0 < 10.0.22631.3155 |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 < 10.0.22631.3155 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoft | 3.1 | 7.6 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:L/E:U/RL:O/RC:C |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: required (a user must click/open something)
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2024-02-13; federal due date 2024-03-05. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active, automatable no, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 27.80% probability of exploitation activity in the next 30 days; percentile 98.
Timeline
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CVE record published by microsoft
- — CISA remediation deadline for US federal agencies
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Windows SmartScreen Security Feature Bypass Vulnerability msrc.microsoft.com
- Listed in CISA KEV notes (msrc.microsoft.com) msrc.microsoft.com
Vulnerability records
- CVE.org record CVE-2024-21351 cve.org
- NVD entry CVE-2024-21351 nvd.nist.gov
Government
All exploited Microsoft vulnerabilities · Today’s Security Digest