Apache Tomcat 4.1.0 through 4.1.39, 5.5.0 through 5.5.27, and 6.0.0 through 6.0.18, when FORM authentication is used, allows remote attackers to enumerate valid usernames via requests to /j_security_check with malformed URL encoding of passwords, related to improper error checking in the (1) MemoryRealm, (2) DataSourceRealm, and (3) JDBCRealm authentication realms, as demonstrated by a % (percent) value for the j_password parameter.

The JK Connector (aka mod_jk) 1.2.0 through 1.2.26 in Apache Tomcat allows remote attackers to obtain sensitive information via an arbitrary request from an HTTP client, in opportunistic circumstances involving (1) a request from a different client that included a Content-Length header but no POST data or (2) a rapid series of requests, related to noncompliance with the AJP protocol's requirements for requests containing Content-Length headers.

Cross-site scripting (XSS) vulnerability in jsp/cal/cal2.jsp in the calendar application in the examples web application in Apache Tomcat 4.1.0 through 4.1.39, 5.5.0 through 5.5.27, and 6.0.0 through 6.0.18 allows remote attackers to inject arbitrary web script or HTML via the time parameter, related to "invalid HTML."

The doRead method in Apache Tomcat 4.1.32 through 4.1.34 and 5.5.10 through 5.5.20 does not return a -1 to indicate when a certain error condition has occurred, which can cause Tomcat to send POST content from one request to a different request.

Apache Tomcat 5.5.0 and 4.1.0 through 4.1.31 allows remote attackers to bypass an IP address restriction and obtain sensitive information via a request that is processed concurrently with another request but in a different thread, leading to an instance-variable overwrite associated with a "synchronization problem" and lack of thread safety, and related to RemoteFilterValve, RemoteAddrValve, and RemoteHostValve.

Apache Tomcat 4.1.0 through 4.1.37, 5.5.0 through 5.5.26, and 6.0.0 through 6.0.16, when a RequestDispatcher is used, performs path normalization before removing the query string from the URI, which allows remote attackers to conduct directory traversal attacks and read arbitrary files via a .. (dot dot) in a request parameter.

Cross-site scripting (XSS) vulnerability in Apache Tomcat 5.5.9 through 5.5.26 and 6.0.0 through 6.0.16 allows remote attackers to inject arbitrary web script or HTML via the name parameter (aka the hostname attribute) to host-manager/html/add.

Apache Tomcat 5.5.11 through 5.5.25 and 6.0.0 through 6.0.15, when the native APR connector is used, does not properly handle an empty request to the SSL port, which allows remote attackers to trigger handling of "a duplicate copy of one of the recent requests," as demonstrated by using netcat to send the empty request.

The default catalina.policy in the JULI logging component in Apache Tomcat 5.5.9 through 5.5.25 and 6.0.0 through 6.0.15 does not restrict certain permissions for web applications, which allows attackers to modify logging configuration options and overwrite arbitrary files, as demonstrated by changing the (1) level, (2) directory, and (3) prefix attributes in the org.apache.juli.FileHandler handler.

Apache Tomcat 6.0.0 to 6.0.13, 5.5.0 to 5.5.24, 5.0.0 to 5.0.30, 4.1.0 to 4.1.36, and 3.3 to 3.3.2 does not properly handle the \" character sequence in a cookie value, which might cause sensitive information such as session IDs to be leaked to remote attackers and enable session hijacking attacks.