---
title: "CVE-2024-21351: Microsoft Windows SmartScreen Security Feature Bypass Vulnerability"
url: https://erroneo.us/security/cve/CVE-2024-21351/
description: "CVE-2024-21351 (Microsoft Windows): Exploited in the wild (CISA KEV). Windows SmartScreen Security Feature Bypass Vulnerability"
type: vulnerability-record
section: "Security Digest"
date_published: 2024-02-13
date_modified: 2026-08-10
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2024-21351"
kev: true
cvss: 7.6
epss: 0.27798
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2024-21351: Microsoft Windows SmartScreen Security Feature Bypass Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- 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

## Affected products (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

- microsoft CVSS 3.1: 7.6 `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`

## Exploitation

- 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.

## Sources

- [Windows SmartScreen Security Feature Bypass Vulnerability](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21351)
- [Listed in CISA KEV notes (msrc.microsoft.com)](https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2024-21351)
- [CVE.org record CVE-2024-21351](https://www.cve.org/CVERecord?id=CVE-2024-21351)
- [NVD entry CVE-2024-21351](https://nvd.nist.gov/vuln/detail/CVE-2024-21351)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-21351)

---
Source page: https://erroneo.us/security/cve/CVE-2024-21351/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt