librack-ruby - several

Several vulnerabilities were discovered in Rack, a modular Ruby
webserver interface. The Common Vulnerabilites and Exposures project
identifies the following vulnerabilities:

• CVE-2011-5036
  Rack computes hash values for form parameters without restricting
  the ability to trigger hash collisions predictably, which allows
  remote attackers to cause a denial of service (CPU consumption)
  by sending many crafted parameters.
• CVE-2013-0183
  A remote attacker could cause a denial of service (memory
  consumption and out-of-memory error) via a long string in a
  Multipart HTTP packet.
• CVE-2013-0184
  A vulnerability in Rack::Auth::AbstractRequest allows remote
  attackers to cause a denial of service via unknown vectors.
• CVE-2013-0263
  Rack::Session::Cookie allows remote attackers to guess the
  session cookie, gain privileges, and execute arbitrary code via a
  timing attack involving an HMAC comparison function that does not
  run in constant time.

For the oldstable distribution (squeeze), these problems have been fixed in
version 1.1.0-4+squeeze1.

The stable, testing and unstable distributions do not contain the
librack-ruby package. They have already been addressed in version
1.4.1-2.1 of the ruby-rack package.

We recommend that you upgrade your librack-ruby packages.