CVE-2023-45648: Apache Tomcat: Trailer header parsing too lenient

[Mark Thomas <markt () apache org>]

Severity: important

Affected versions:

- Apache Tomcat 11.0.0-M1 through 11.0.0-M11
- Apache Tomcat 10.1.0-M1 through 10.1.13
- Apache Tomcat 9.0.0-M1 through 9.0.81
- Apache Tomcat 8.5.0 through 8.5.93

Description:

Improper Input Validation vulnerability in Apache Tomcat.Tomcat from 
11.0.0-M1 through 11.0.0-M11, from 10.1.0-M1 through 10.1.13, from 
9.0.0-M1 through 9.0.81 and from 8.5.0 through 8.5.93 did not correctly 
parse HTTP trailer headers. A specially
crafted, invalid trailer header 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-M12 onwards, 10.1.14 
onwards, 9.0.81 onwards or 8.5.94 onwards, which fix the issue.

Credit:

Keran Mu and Jianjun Chen from Tsinghua University and Zhongguancun 
Laboratory (finder)

References:

https://lists.apache.org/thread/2pv8yz1pyp088tsxfb7ogltk9msk0jdp
https://tomcat.apache.org/
https://www.cve.org/CVERecord?id=CVE-2023-45648