Apache httpd 2.0.59 and 2.2.4, with the Prefork MPM module, allows local users to cause a denial of service via certain code sequences executed in a worker process that (1) stop request processing by killing all worker processes and preventing creation of replacements or (2) hang the system by forcing the master process to fork an arbitrarily large number of worker processes. NOTE: This might be an inherent design limitation of Apache with respect to worker processes in hosted environments.

The recall_headers function in mod_mem_cache in Apache 2.2.4 does not properly copy all levels of header data, which can cause Apache to return HTTP headers containing previously used data, which could be used by remote attackers to obtain potentially sensitive information.