The Apache HTTP server is a very widely used web server. mod_jk provides the JK module for connecting Tomcat and Apache using the ajp13 protocol.
ZDI reported an unsafe memory copy in mod_jk that was discovered by an anonymous researcher in the map_uri_to_worker function of native/common/jk_uri_worker_map.c .
A remote attacker can send a long URL request to an Apache server using Tomcat. That can trigger the vulnerability and lead to a stack-based buffer overflow, which could result in the execution of arbitrary code with the permissions of the Apache user.
There is no known workaround at this time.
All Apache Tomcat users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=www-apache/mod_jk-1.2.21-r1"