CVE-2011-5279: Microsoft Internet Information Services

Medium severity, CVSS 5.0. EPSS: 19.6% chance of exploitation in the next 30 days.

CRLF injection vulnerability in the CGI implementation in Microsoft Internet Information Services (IIS) 4.x and 5.x on Windows NT and Windows 2000 allows remote attackers to modify arbitrary uppercase environment variables via a \n (newline) character in an HTTP header.

Affected products

• Microsoft Internet Information Services: version 4.0 only; version 5.0 only

Published 2014-04-23. Last modified 2026-06-16.