View at Official ubuntu advisory, NVD, CVE.org · CVE detail
Freshness: upstream tracker timestamp is available; use API updated time as primary recency signal.
CVE-2011-4858 medium priority: Ubuntu including 3 source packages (tomcat5.5, tomcat6, tomcat7), 24 status rows across 8 suites (hardy, lucid, maverick, natty, oneiric, precise, quantal, upstream): DNE 11, released 8, not-affected 4, ignored 1.
Apache Tomcat before 5.5.35, 6.x before 6.0.35, and 7.x before 7.0.23 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.