CVE-2024-21351: Microsoft Windows SmartScreen Security Feature Bypass Vulnerability
Affects Microsoft WindowsSource CISA KEV
Exploited in the wild · KEV due 5 Mar 2024 · 27% EPSS : apply the vendor's fix or mitigations to Microsoft Windows now.
Data as of 10/24/2026, 22:15:59 UTC
- Exploitation
Actively exploited – in CISA KEV since 02/13/2024
- KEV deadline
- 03/05/2024 US federal agencies must patch by this date; a sensible deadline for everyone else.
- EPSS
- 27.7% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:L/E:U/RL:O/RC:CWhat to do
CISA required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Description
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.
Weaknesses
- CWE-94Improper Control of Generation of Code ('Code Injection') (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #10OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.