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CVE-2009-3677

HIGH · CVSS 10.0EPSS 21.8%EU EUVD

The Internet Authentication Service (IAS) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold and SP1, and Server 2008 Gold does not properly verify the credentials in an MS-CHAP v2 Protected Extensible Authentication Protocol (PEAP) authentication request, which allows remote attackers to access network resources via a malformed request, aka "MS-CHAP Authentication Bypass Vulnerability."

Key facts

CVSS score
10.0 (v2.0)
Severity
HIGH
CVSS vector
AV:N/AC:L/Au:N/C:C/I:C/A:C
Weakness (CWE)
CWE-94
EPSS score
21.8% (98th percentile)
In CISA KEV
No
In EU EUVD
Yes (EUVD-2009-3652)
Published
December 9, 2009
NVD last modified
June 16, 2026
Status
Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2009-3652 in the EU Vulnerability Database. Last updated in EUVD on August 7, 2024.

View on the EU Vulnerability Database

Affected products

  • microsoft / windows 2000
  • microsoft / windows server 2003
  • microsoft / windows server 2008
  • microsoft / windows server 2008
  • microsoft / windows server 2008
  • microsoft / windows vista
  • microsoft / windows vista
  • microsoft / windows vista
  • microsoft / windows xp
  • microsoft / windows xp
  • microsoft / windows xp

Certified products that may be affected

11 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

See all 11 in the Security Certifications Explorer.

References

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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