Microsoft ASP.NET Core Security Feature Bypass Vulnerability
At a glance
Severity
HIGH 7.5
EPSS
EPSS 5.93 % · percentile 93 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
microsoft
NVD status
Modified
Description
<p>A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.</p>
<p>The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded.</p>
<p>The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.</p>
