Julian Wälde and Alexander Klink reported a way to degrade performance of the Java HashMap and HashTable implementations by filling the hash table with keys with identical hash codes. See bug #750533 for details. This issue can be used to mount an efficient details of service attack against GlassFish application server. GlassFish parses HTTP request parameters and stores them in a hash table. A remote attacker could use this flaw to make the GlassFish java process use an excessive amount of CPU time by sending a POST request with a large number of parameters which hash to the same value.
Not vulnerable. This issue affects the GlassFish Web Container component. This
component is not shipped with any Red Hat products. JBoss Web and Tomcat
provide the web container used in all JBoss products.
Note that this CVE was also used for the HttpServer class in the standard Java Class Library, which did not limit the number of HTTP headers read from HTTP requests and stored in the HashMap, hence allowing the hash collision to be triggered. That issue is tracked via separate bug #788606.