Apache Httpd < 2.2.16 : mod_cache and mod_dav DoS

A flaw was found in the handling of requests by mod_cache (2.2) and mod_dav (2.0 and 2.2). A malicious remote attacker could send a carefully crafted request and cause a httpd child process to crash. This crash would only be a denial of service if using the worker MPM. This issue is further mitigated as mod_dav is only affected by requests that are most likely to be authenticated, and mod_cache is only affected if the uncommon “CacheIgnoreURLSessionIdentifiers” directive, introduced in version 2.2.14, is used.