Vulnerability record · CVE-2006-2766 · published 2 June 2006
CVE-2006-2766: Microsoft INETCOMM.DLL Buffer Overflow via Long MHTML URI
Microsoft · Ie
A buffer overflow exists in INETCOMM.DLL, a component used by Internet Explorer 6.0 through 6.0 SP2, Windows Explorer, and Outlook Express 6. A remote attacker can trigger it by placing a long mhtml URI in the URL value of a URL file, causing an application crash. The flaw is a denial-of-service issue rather than a code-execution primitive per the available description.
Description
Buffer overflow in INETCOMM.DLL, as used in Microsoft Internet Explorer 6.0 through 6.0 SP2, Windows Explorer, Outlook Express 6, and possibly other programs, allows remote user-assisted attackers to cause a denial of service (application crash) via a long mhtml URI in the URL value in a URL file.
AV:N/AC:H/Au:N/C:N/I:N/A:P
Automated analysis
medium priorityImpact is limited to denial of service and requires user interaction, but a public exploit reference and high EPSS score raise the practical risk.
What it is
A buffer overflow exists in INETCOMM.DLL, a component used by Internet Explorer 6.0 through 6.0 SP2, Windows Explorer, and Outlook Express 6. A remote attacker can trigger it by placing a long mhtml URI in the URL value of a URL file, causing an application crash. The flaw is a denial-of-service issue rather than a code-execution primitive per the available description.
Impact
An attacker can crash the affected application, causing a denial of service on the victim's system. The record describes only availability impact (C:N/I:N/A:P), so no confidentiality or integrity loss is established.
Attack surface
Reached remotely over the network via a crafted URL file containing an oversized mhtml URI, but the CVSS vector marks access complexity as high and requires user assistance (opening the file). No authentication is needed, but the victim must interact with the malicious file.
Exploitation
Not listed in CISA KEV, but a public exploit reference exists (SecurityFocus BID 18198 tagged Exploit) and EPSS is high at roughly 0.48 (98.8th percentile), indicating elevated likelihood of exploitation activity.
What to do
- Apply the Microsoft security update referenced in MS06-043, which addresses this INETCOMM.DLL issue.
- Upgrade or retire Internet Explorer 6.x and Outlook Express 6, which are long out of support.
- Block or restrict opening of untrusted .url files and mhtml URIs via email and web gateways.
- Warn users not to open URL files or links from untrusted sources, since the attack requires user assistance.
Detection
- Monitor for application crashes in iexplore.exe, explorer.exe, or msimn.exe tied to INETCOMM.DLL.
- Alert on .url files containing unusually long mhtml: URI values in email attachments or downloads.
- Review endpoint logs for repeated process crashes following user opening of URL files from external sources.
This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.
Affected products
2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
Track CVE-2006-2766 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2006-2766), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
