Improper Handling of Length Parameter Inconsistency

Summary

The package Jetty in versions 9.0.x prior to 9.4.52.v20230823, 10.0.x prior to 10.0.16, 11.0.x prior to 11.0.16 and 12.0.x prior to 12.0.1 accepts the '+' character proceeding the content-length value in a HTTP/1 header field. This is more permissive than allowed by the RFC and other servers routinely reject such requests with 400 responses. There is no known exploit scenario, but it is conceivable that request smuggling could result if jetty is used in combination with a server that does not close the connection after sending such a 400 response.