The Cisco Content Services Switch (CSS) 11500 with software before 8.20.4.02 and the Application Control Engine (ACE) 4710 with software before A2(3.0) do not properly handle use of LF, CR, and LFCR as alternatives to the standard CRLF sequence between HTTP headers, which allows remote attackers to bypass intended header insertions or conduct HTTP request smuggling attacks via crafted header data, as demonstrated by LF characters preceding ClientCert-Subject and ClientCert-Subject-CN headers, aka Bug ID CSCta04885.
