CVE-2009-3677
The Internet Authentication Service (IAS) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server...
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."
Exploit likelihood
What each source reports
NVD Score used
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."
- Record
CVE-2009-3677- CVSS 2.0
- 10.0 High
AV:N/AC:L/Au:N/C:C/I:C/A:C - Weakness
- CWE-94, CWE-255
- Updated
- 2026-11-02
CVE List No score
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."
- Record
CVE-2009-3677- Updated
- 2026-11-02
EUVDEUVD-2009-3652 No score
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."
- Record
EUVD-2009-3652- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-24hh-hrh3-7p5w No score
The Internet Authentication Service (IAS) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server...
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."
- Record
GHSA-24hh-hrh3-7p5w- Weakness
- CWE-94
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2009-3677 is a high vulnerability (CVSS 10.0) in Microsoft Windows 2000, published December 9, 2009. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 21.8%, the 97th percentile. No source names a fixed version.
References
docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-071
us-cert.gov/cas/techalerts/TA09-342A.html
securitytracker.com/id?1023291
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6209
nvd.nist.gov/vuln/detail/CVE-2009-3677
github.com/advisories/GHSA-24hh-hrh3-7p5w