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CVE-2009-2505· NVD / CVE Program· CNA microsoft

The Internet Authentication Service (IAS) in Microsoft Windows Vista SP2 and Server 2008 SP2 does not properly validate MS-CHAP v2 Protected

The Internet Authentication Service (IAS) in Microsoft Windows Vista SP2 and Server 2008 SP2 does not properly validate MS-CHAP v2 Protected Extensible Authentication Protocol (PEAP) authentication requests, which allows remote attackers to execute arbitrary code via crafted structures in a malformed request, aka "Internet Authentication Service Memory Corruption Vulnerability."

CriticalCVSS 10.0 · v2.0—No exploit No fix recorded
Published
Dec 9, 2009
Updated
Jun 16, 2026
EPSS
31.6% · 98th percentile
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Report tools

JSON

Action score

49

Plan

Add it to your regular patch cycle.

CVSS
40 / 40 · 10.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
9 / 30 · 31.6%

Affected systems

VendorProduct
microsoftwindows server 2008
microsoftwindows vista

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • microsoft windows server 2008all versions
  • microsoft windows server 2008sp2

Same product

microsoft: all records

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • No special conditions are required; it is repeatable.

If successful

Confidentiality
C · data can be read
Integrity
C · data or configuration can be modified
Availability
C · the service can be disrupted
Attack complexity
Low
Confidentiality impact
C
Integrity impact
C
Availability impact
C

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

nvd-primary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);

Fixed

ts
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records