The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

When running Apache Tomcat versions 9.0.0.M1 to 9.0.0, 8.5.0 to 8.5.22, 8.0.0.RC1 to 8.0.46 and 7.0.0 to 7.0.81 with HTTP PUTs enabled (e.g. via setting the readonly initialisation parameter of the Default servlet to false) it was possible to upload a JSP file to the server via a specially crafted request. This JSP could then be requested and any code it contained would be executed by the server.

Apache Tomcat 10.0.0-M1 to 10.0.6, 9.0.0.M1 to 9.0.46 and 8.5.0 to 8.5.66 did not correctly parse the HTTP transfer-encoding request header in some circumstances leading to the possibility to request smuggling when used with a reverse proxy. Specifically: - Tomcat incorrectly ignored the transfer encoding header if the client declared it would only accept an HTTP/1.0 response; - Tomcat honoured the identify encoding; and - Tomcat did not ensure that, if present, the chunked encoding was the final encoding.

An improper handing of overflow in the UTF-8 decoder with supplementary characters can lead to an infinite loop in the decoder causing a Denial of Service. Versions Affected: Apache Tomcat 9.0.0.M9 to 9.0.7, 8.5.0 to 8.5.30, 8.0.0.RC1 to 8.0.51, and 7.0.28 to 7.0.86.

A bug in the handling of the pipelined requests in Apache Tomcat 9.0.0.M1 to 9.0.0.M18, 8.5.0 to 8.5.12, 8.0.0.RC1 to 8.0.42, 7.0.0 to 7.0.76, and 6.0.0 to 6.0.52, when send file was used, results in the pipelined request being lost when send file processing of the previous request completed. This could result in responses appearing to be sent for the wrong request. For example, a user agent that sent requests A, B and C could see the correct response for request A, the response for request C for request B and no response for request C.

The code in Apache Tomcat 9.0.0.M1 to 9.0.0.M11, 8.5.0 to 8.5.6, 8.0.0.RC1 to 8.0.38, 7.0.0 to 7.0.72, and 6.0.0 to 6.0.47 that parsed the HTTP request line permitted invalid characters. This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation, to inject data into the HTTP response. By manipulating the HTTP response the attacker could poison a web-cache, perform an XSS attack and/or obtain sensitive information from requests other then their own.

The session-persistence implementation in Apache Tomcat 6.x before 6.0.45, 7.x before 7.0.68, 8.x before 8.0.31, and 9.x before 9.0.0.M2 mishandles session attributes, which allows remote authenticated users to bypass intended SecurityManager restrictions and execute arbitrary code in a privileged context via a web application that places a crafted object in a session.

Apache Tomcat 6.x before 6.0.45, 7.x before 7.0.68, 8.x before 8.0.31, and 9.x before 9.0.0.M2 does not place org.apache.catalina.manager.StatusManagerServlet on the org/apache/catalina/core/RestrictedServlets.properties list, which allows remote authenticated users to bypass intended SecurityManager restrictions and read arbitrary HTTP requests, and consequently discover session ID values, via a crafted web application.

The Mapper component in Apache Tomcat 6.x before 6.0.45, 7.x before 7.0.68, 8.x before 8.0.30, and 9.x before 9.0.0.M2 processes redirects before considering security constraints and Filters, which allows remote attackers to determine the existence of a directory via a URL that lacks a trailing / (slash) character.

Directory traversal vulnerability in RequestUtil.java in Apache Tomcat 6.x before 6.0.45, 7.x before 7.0.65, and 8.x before 8.0.27 allows remote authenticated users to bypass intended SecurityManager restrictions and list a parent directory via a /.. (slash dot dot) in a pathname used by a web application in a getResource, getResourceAsStream, or getResourcePaths call, as demonstrated by the $CATALINA_BASE/webapps directory.