CVE-2002-0155
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBuffer overflow in Microsoft MSN Chat ActiveX Control, as used in MSN Messenger 4.5 and 4.6, and Exchange Instant Messenger 4.5 and 4.6, allows remote attackers to execute arbitrary code via a long ResDLL parameter in the MSNChat OCX.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceBuffer overflow vulnerability in the MSN Chat ActiveX control (MSNChat.ocx) used by MSN Messenger 4.5/4.6 and Exchange Instant Messenger 4.5/4.6. The flaw is triggered by passing an excessively long string to the ResDLL parameter, which can overwrite memory and allow remote arbitrary code execution.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versions= 4.5= 4.6= 4.5= 4.6CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/A:P
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check if MSN Messenger is installedOpen Windows Control Panel, go to Add or Remove Programs (or Programs and Features), look for 'MSN Messenger' or 'Microsoft MSN Messenger' in the installed program list and note the version numberAffected if The installed version is 4.5 or 4.6
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Check if Exchange Instant Messenger is installedOpen Windows Control Panel, go to Add or Remove Programs (or Programs and Features), look for 'Exchange Instant Messenger' or 'Microsoft Exchange Instant Messaging' and note the version numberAffected if The installed version is 4.5 or 4.6
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Locate the MSNChat.ocx ActiveX controlSearch for the file MSNChat.ocx on the system using Windows Explorer search or the command 'dir /s C:\MSNChat.ocx' from an elevated command promptAffected if The file MSNChat.ocx exists on the system in any directory (common locations include C:\Windows\System32 or C:\Windows\Downloaded Program Files)
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Check if the ActiveX control is registeredOpen Windows Registry Editor and navigate to HKLM\SOFTWARE\Microsoft\Code Store Database\Distribution Units\{F6A84C60-A42B-4BC8-AA60-8B1C1EF7EC79} or search for the CLSID {F6A84C60-A42B-4BC8-AA60-8B1C1EF7EC79} under HKLM or HKCU\Software\Classes\CLSIDAffected if The ActiveX control CLSID is registered in the Windows Registry
A user is affected if MSN Messenger 4.5 or 4.6, or Exchange Instant Messenger 4.5 or 4.6 is installed, OR if the MSNChat.ocx ActiveX control exists and is registered on the system regardless of software version.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataDisable or remove the vulnerable MSN Chat ActiveX control. Since these versions of MSN Messenger and Exchange Instant Messenger are from 2002 and are end-of-life, the recommended remediation is to uninstall the affected software or ensure the ActiveX control is not loaded by browsers.
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- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2002-0155 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2002-0155 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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