CVE-2000-0991: Buffer overflow in Hilgraeve, Inc.

Security readout for executives and security teams

A flaw in the HyperTerminal client bundled with older Windows versions let an attacker take control of a user's PC if that user clicked a specially crafted telnet link. The victim had to open the malicious link, but success would give the attacker the same access as the logged-in user. Microsoft addressed the issue in bulletin MS00-079 back in 2000. Exposure is limited to legacy Windows 98, ME, or 2000 systems that still have HyperTerminal registered as the telnet URL handler. Modern supported Windows releases do not ship this component and are unaffected. Any remaining exposure would sit in isolated OT, kiosk, or archival environments running end-of-life operating systems. Very low priority for any modern estate. Treat as informational unless the environment still operates Windows 98, ME, or 2000, in which case bundle remediation into the broader legacy-system retirement plan rather than a standalone patch cycle. Mitigation focus: Apply the Microsoft MS00-079 patch on any surviving Windows 98, ME, or 2000 hosts.; Retire or air-gap legacy Windows systems still running HyperTerminal wherever business use permits.; Unregister or remove telnet:// URL handling on affected endpoints if the patch cannot be applied..

Prepared

Jul 11, 2026, 23:58 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.