CVE-2009-3677

NONECVSS 0.0Elevated
0.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No confirmed exploitation signals yet
CISA-KEV: Not listedEPSS: 22%CVSS: —Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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."

CVSS v3
—
EG Score
0.0(none)
EG Risk
0
EG Risk 0/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses intrinsic severity with real-world exploitation and automatability, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. It is distinct from the 0–10 EG Score, which measures severity.

EPSS
97.4%
KEV
Not listed

Published

December 9, 2009

Last Modified

April 23, 2026

References (8)

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 33× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:14 UTCEPSS rescore
  2. 2026-07-23 01:00 UTCEG score recompute
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  44. 2026-05-30 14:23 UTCEG score recompute
  45. 2026-05-30 14:23 UTCGHSA enrichment
  46. 2026-05-28 13:42 UTCEPSS rescore
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  59. 2026-05-18 21:29 UTCEPSS rescore

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Frequently asked(4)

What is CVE-2009-3677?
CVE-2009-3677 is a none vulnerability published on December 9, 2009. 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…
When was CVE-2009-3677 disclosed?
CVE-2009-3677 was first published in the National Vulnerability Database on December 9, 2009, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2009-3677 actively exploited?
CVE-2009-3677 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 97.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
How do I remediate CVE-2009-3677?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-3677, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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