Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.
This is generally found in proxies, firewalls, anti-virus software, and other intermediary devices that monitor, allow, deny, or modify traffic based on how the client or server is expected to behave.
CVE-2005-1215Bypass filters or poison web cache using requests with multiple Content-Length headers, a non-standard behavior.
CVE-2002-0485Anti-virus product allows bypass via Content-Type and Content-Disposition headers that are mixed case, which are still processed by some clients.
CVE-2002-1978FTP clients sending a command with "PASV" in the argument can cause firewalls to misinterpret the server's error as a valid response, allowing filter bypass.
CVE-2002-1979FTP clients sending a command with "PASV" in the argument can cause firewalls to misinterpret the server's error as a valid response, allowing filter bypass.
CVE-2002-0637Virus product bypass with spaces between MIME header fields and the ":" separator, a non-standard message that is accepted by some clients.