Red Hat Enterprise Linux 4,5: RHSA-2008:0897-01 Moderate: Ruby DoS Issues

Ruby is an interpreted scripting language for quick and easy object-oriented programming.
The Ruby DNS resolver library, resolv.rb, used predictable transaction IDs and a fixed source port when sending DNS requests. A remote attacker could use this flaw to spoof a malicious reply to a DNS query. (CVE-2008-3905)
Ruby's XML document parsing module (REXML) was prone to a denial of service attack via XML documents with large XML entity definitions recursion. A specially-crafted XML file could cause a Ruby application using the REXML module to use an excessive amount of CPU and memory. (CVE-2008-3790)
An insufficient "taintness" check flaw was discovered in Ruby's DL module, which provides direct access to the C language functions. An attacker could use this flaw to bypass intended safe-level restrictions by calling external C functions with the arguments from an untrusted tainted inputs. (CVE-2008-3657)
A denial of service flaw was discovered in WEBrick, Ruby's HTTP server toolkit. A remote attacker could send a specially-crafted HTTP request to a WEBrick server that would cause the server to use an excessive amount of CPU time. (CVE-2008-3656)
A number of flaws were found in the safe-level restrictions in Ruby. It was possible for an attacker to create a carefully crafted malicious script that can allow the bypass of certain safe-level restrictions. (CVE-2008-3655)
A denial of service flaw was found in Ruby's regular expression engine. If a Ruby script tried to process a large amount of data via a regular expression, it could cause Ruby to enter an infinite-loop and crash. (CVE-2008-3443)
Users of ruby should upgrade to these updated packages, which contain backported patches to resolve these issues.