Is CVE-2009-3677 in the CISA KEV catalog?

No. CVE-2009-3677 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2009-3677?

CVE-2009-3677 has a CVSS v2 base score of 10.0 (HIGH).

What is the EPSS score for CVE-2009-3677?

CVE-2009-3677 has an EPSS score of 21.82% (97th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2009-3677?

No published fix for CVE-2009-3677 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2009-3677

HIGHEPSS 97th pctl

10.0

CVSS v2

NVD

Description

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."

CWE-94Code Injection CWE-255

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

TridentStack Control tracks known vulnerabilities across your Windows, macOS, and Linux fleet and shows the fix as soon as one is published. See how it works

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

21.82%probability of exploitation in 30 days

97thpercentile

Very high risk: more likely to be exploited than 97% of all known CVEs.

References

Government Resource1

us-cert.gov

Other references3

Related Vulnerabilities

Other CWE-94 (Code Injection) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2017-9841	Critical	9.8	100%	KEV	Fix
CVE-2015-1635	Critical	9.8	100%	KEV	-
CVE-2022-22954	Critical	9.8	100%	KEV + Ransom	-
CVE-2025-3248	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2021-22204	Medium	6.8	100%	KEV	Fix
CVE-2012-0158	High	8.8	100%	KEV	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-23.