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

Source: https://junglewise.ai/threats/cve-2021-34448-microsoft-windows-scripting-engine-memory-corruption  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-11-03. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2021-34448 · Severity: critical · CVSS 8.8 · Exploited in the wild · Published 2021-11-03

The Microsoft Windows Scripting Engine contains a memory corruption vulnerability caused by an out-of-bounds write (CWE-787). An attacker could exploit this by convincing a user to visit a specially crafted website or open a malicious file, potentially leading to remote code execution.

Technologies: [Microsoft Windows](https://junglewise.ai/threats/technologies/windows). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2021-34448 exploited in the wild?** Yes. CVE-2021-34448 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.

**How severe is CVE-2021-34448?** Critical severity, with a CVSS score of 8.8, published 3 November 2021.

**Which products and versions are affected?** Microsoft Windows 10 up to (excluding) 10.0.10240.19003; Microsoft Windows 10 Version 1607 up to (excluding) 10.0.14393.4530; Microsoft Windows 10 Version 1809 up to (excluding) 10.0.17763.2061; Microsoft Windows 10 Version 1909 up to (excluding) 10.0.18363.1679; and 11 more.

**Is there a fix for CVE-2021-34448?** A patch was published on 2021-07-22: Initial NIST analysis and patch reference added Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2021-34448 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2021-34448?** Check whether you run Microsoft Windows. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Microsoft Windows 10 up to (excluding) 10.0.10240.19003
- Microsoft Windows 10 Version 1607 up to (excluding) 10.0.14393.4530
- Microsoft Windows 10 Version 1809 up to (excluding) 10.0.17763.2061
- Microsoft Windows 10 Version 1909 up to (excluding) 10.0.18363.1679
- Microsoft Windows 10 Version 2004 up to (excluding) 10.0.19041.1110
- Microsoft Windows 10 Version 20H2 up to (excluding) 10.0.19042.1110
- Microsoft Windows 10 Version 21H1 up to (excluding) 10.0.19043.1110
- Microsoft Windows 7 Service Pack 1
- Microsoft Windows 8.1
- Microsoft Windows RT 8.1
- Microsoft Windows Server 2008 R2 Service Pack 1
- Microsoft Windows Server 2012
- Microsoft Windows Server 2012 R2
- Microsoft Windows Server 2016 up to (excluding) 10.0.14393.4530
- Microsoft Windows Server 2019 up to (excluding) 10.0.17763.2061

## Timeline

- 2021-07-13: disclosed: MSRC Advisory Published
- 2021-07-22: patched: Initial NIST analysis and patch reference added
- 2021-11-03: kev added: Added to CISA Known Exploited Vulnerabilities Catalog
- 2021-11-03: exploited: Confirmed exploited in the wild per CISA KEV catalog and advisory report.

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