Uncontrolled Resource Consumption
The HTTP/2 implementation in Apache Tomcat accepted streams with excessive numbers of `SETTINGS` frames and also permitted clients to keep streams open without reading/writing request/response data. By keeping streams open for requests that utilised the Servlet API's blocking I/O, clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.
Improper Input Validation
When running on Windows with `enableCmdLineArguments` enabled, the CGI Servlet in Apache Tomcat is vulnerable to Remote Code Execution due to a bug in the way the JRE passes command line arguments to Windows. The CGI Servlet is disabled by default. The CGI option `enableCmdLineArguments` is disable by default in Tomcat (and will be disabled by default in all versions in response to this vulnerability).
Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)
Tomcat contains a race condition that could result in a user seeing a response intended for a different user.
Cross-site Scripting
The SSI printenv command in Apache Tomcat echoes user provided data without escaping and is, therefore, vulnerable to XSS. SSI is disabled by default. The `printenv` command is intended for debugging and is unlikely to be present in a production website.
Loop with Unreachable Exit Condition (Infinite Loop)
An improper handling of overflow in the UTF-8 decoder with supplementary characters can lead to an infinite loop in the decoder causing a Denial of Service.
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in FORM authentication feature Apache Tomcat.This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.0-M10, from 10.1.0-M1 through 10.0.12, from 9.0.0-M1 through 9.0.79 and from 8.5.0 through 8.5.92.
The vulnerability is limited to the ROOT (default) web application.
Uncontrolled Resource Consumption
The fix for CVE-2019-0199 was incomplete and did not address HTTP/2 connection window exhaustion on write in Apache Tomcat. By not sending `WINDOW_UPDATE` messages for the connection window (stream 0) clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Improper Input Validation vulnerability in Apache Tomcat.Tomcat from 11.0.0-M1 through 11.0.0-M10, from 10.1.0-M1 through 10.1.15, from 9.0.0-M1 through 9.0.82 and from 8.5.0 through 8.5.95 does not correctly parse HTTP trailer headers. A trailer header that exceeded the header size limit could cause Tomcat to treat a single
request as multiple requests leading to the possibility of request
smuggling when behind a reverse proxy.
Users are recommended to upgrade to version 11.0.0-M11Â onwards, 10.1.16 onwards, 9.0.83 onwards or 8.5.96 onwards, which fix the issue.