CVE-2008-3843: Request Validation (aka the ValidateRequest filters) in ASP.NET in Microsoft .NET Framework with the MS07-0...

Security readout for executives and security teams

This issue is an old ASP.NET cross-site scripting weakness. Microsoft .NET Framework request validation could miss dangerous input, so an attacker might get script-like content reflected through a vulnerable web application. Business impact depends on whether legacy ASP.NET applications still rely on this filter as their main XSS defense. Exposure is most plausible in legacy ASP.NET applications using affected Microsoft .NET Framework behavior and relying on ValidateRequest to block malicious request data. The bundle does not provide exact supported versions, CPEs, or a complete affected product matrix. Address during legacy web application risk reduction, with higher priority for internet-facing ASP.NET systems handling authenticated sessions or sensitive data. No active exploitation evidence is provided, but the weakness undermines a commonly trusted defensive filter. Mitigation focus: Check Microsoft or vendor guidance for applicable framework updates or configuration changes.; Do not rely on ValidateRequest as the only XSS control.; Review affected ASP.NET pages for context-aware output encoding..

Prepared

Jun 28, 2026, 18:33 UTC (UTC+00:00)

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