It was discovered that the code that parsed the HTTP request line permittedinvalid characters. This could be exploited, in conjunction with a proxy thatalso permitted the invalid characters but with a different interpretation, toinject data into the HTTP response. By manipulating the HTTP response theattacker could poison a web-cache, perform an XSS attack, or obtain sensitiveinformation from requests other then their own. Note: This fix causes Tomcat to respond with an HTTP 400 Bad Request error whenrequest contains characters that are not permitted by the HTTP specification toappear not encoded, even though they were previously accepted. The newlyintroduced system property tomcat.util.http.parser.HttpParser.requestTargetAllowcan be used to configure Tomcat to accept curly braces and the pipesymbol in not encoded form, as these are often used in URLs without beingproperly encoded. * A bug was discovered in the error handling of the send file code for the NIOHTTP connector. This led to the current Processor object being added to theProcessor cache multiple times allowing information leakage between requestsincluding, and not limited to, session ID and the response body