# Microsoft February 2024: 2 actively exploited zero-days · pwn.watch

> CVE-2024-21351: 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. CVE-2024-21412: Microsoft Windows Internet Shortcut Files contains an unspecified vulnerability that allows for a security feature bypass. Added to the CISA KEV catalog on 2024-02-13. CISA lists known use in ransomware campaigns.

Page: https://pwn.watch/i/microsoft-zero-days-february-2024-21351-21412 · generated 2026-10-23T00:25:11.801Z

## Status
- Severity: high · status: closed · patch: patched
- Product: Microsoft Windows
- Started: 2024-02-13 · closed: 2024-02-13
- CVEs: CVE-2024-21351, CVE-2024-21412
- Affected: See vendor advisory (versions are not listed in the KEV record)
- Fixed in: See vendor advisory linked in sources

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/microsoft-zero-days-february-2024-21351-21412/feed.xml
- JSON Feed: https://pwn.watch/i/microsoft-zero-days-february-2024-21351-21412/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/microsoft-zero-days-february-2024-21351-21412.json
- This file: https://pwn.watch/i/microsoft-zero-days-february-2024-21351-21412/llms.txt

## Updates (newest first)
- 2024-02-13: CVE-2024-21351 published (https://nvd.nist.gov/vuln/detail/CVE-2024-21351)
- 2024-02-13: CVE-2024-21412 published (https://nvd.nist.gov/vuln/detail/CVE-2024-21412)
- 2024-02-13: CISA added CVE-2024-21351 to the KEV catalog (federal deadline 2024-03-05) (https://www.cisa.gov/known-exploited-vulnerabilities-catalog)
- 2024-02-13: CISA added CVE-2024-21412 to the KEV catalog (federal deadline 2024-03-05) (https://www.cisa.gov/known-exploited-vulnerabilities-catalog)

## Fix brief
# Security brief: Microsoft February 2024: 2 actively exploited zero-days

Source: https://pwn.watch/i/microsoft-zero-days-february-2024-21351-21412 · status: closed (closed Feb 13, 2024) · severity: high · updated Feb 13, 2024

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
CVE-2024-21351: 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. CVE-2024-21412: Microsoft Windows Internet Shortcut Files contains an unspecified vulnerability that allows for a security feature bypass. Added to the CISA KEV catalog on 2024-02-13. CISA lists known use in ransomware campaigns.

Severity detail: CVSS 8.1 (v3.1, CNA), actively exploited (CISA KEV); known ransomware use

- Product: Microsoft Windows
- CVE / advisory ids: CVE-2024-21351, CVE-2024-21412

## Affected versions
- See vendor advisory (versions are not listed in the KEV record)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- See vendor advisory linked in sources

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Feb 13, 2024: CVE-2024-21351 published
- Feb 13, 2024: CVE-2024-21412 published
- Feb 13, 2024: CISA added CVE-2024-21351 to the KEV catalog (federal deadline 2024-03-05)
- Feb 13, 2024: CISA added CVE-2024-21412 to the KEV catalog (federal deadline 2024-03-05)

## Advisories
- [Microsoft advisory: CVE-2024-21351](https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2024-21351) (Microsoft)
- [Microsoft advisory: CVE-2024-21412](https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2024-21412) (Microsoft)
- [NVD: CVE-2024-21351](https://nvd.nist.gov/vuln/detail/CVE-2024-21351) (NVD)
- [NVD: CVE-2024-21412](https://nvd.nist.gov/vuln/detail/CVE-2024-21412) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Caveats
Derived from the CISA KEV JSON feed (catalogVersion 2026.10.21); CVSS from the CVE record (cveawg.mitre.org). startedAt is the CVE publication date when it fell in 2024 before the KEV listing, else the KEV dateAdded; exploitation may have begun earlier. closedAt is the KEV listing date (a fix or mitigation was available then unless noted).

---
Machine-readable: https://pwn.watch/i/microsoft-zero-days-february-2024-21351-21412.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.