CVE-2006-3086: Microsoft Hyperlink Object Library hlink.dll stack buffer overflow

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 19 September 2026. Confidence: medium.

high priorityCVSS 9.3 and very high EPSS with public exploit references, though no KEV listing and the flaw is from 2006.

What it is

The HrShellOpenWithMonikerDisplayName function in Microsoft's Hyperlink Object Library (hlink.dll) has a stack-based buffer overflow triggered by an overly long hyperlink, demonstrated via an Excel worksheet containing a long Unicode link. Successful exploitation can crash the application and potentially allow arbitrary code execution in the context of the affected process.

Impact

An attacker can cause a denial of service and, per the record, possibly execute arbitrary code with the privileges of the user or application processing the link.

Attack surface

Reached remotely over the network (AV:N) by supplying a crafted hyperlink, for example inside an Excel worksheet; no authentication is required (Au:N), but the CVSS vector indicates medium attack complexity (AC:M), implying some conditions or user interaction such as opening the document.

Exploitation

Not listed in CISA KEV, but EPSS is high (0.56461, 99th percentile) and a SecurityFocus reference is tagged Exploit, indicating public exploit information exists.

What to do

• Apply the Microsoft security update referenced in MS06-050 (and vendor advisories) to fix hlink.dll.
• Block or strip hyperlinks and untrusted Office documents from external sources at email and web gateways.
• Disable or restrict automatic hyperlink resolution in Office applications where feasible.
• Enforce least privilege so users do not run with administrative rights, limiting post-exploitation impact.

Detection

• Monitor for crashes of Excel or other Office processes involving hlink.dll.
• Search endpoint logs for hlink.dll faults or stack overflow exceptions tied to document opening.
• Inspect email and file transfer logs for Office documents containing unusually long hyperlink fields.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.