CVE-2012-5370: JRuby denial of service via Hash Collision

The vulnerability CVE-2012-5370 stems from JRuby's use of MurmurHash2, which is susceptible to collision attacks. The commit diff shows that the fix replaced the hash implementation in RubyString.java's strHashCode() and unseededStrHashCode() methods with PerlHash. Prior to the patch, these methods used a vulnerable algorithm (implied to be MurmurHash2 based on CVE details), leading to predictable collisions. The confidence is high because the commit directly modifies these functions to address the issue, and the CVE explicitly links hash collisions to the MurmurHash2 algorithm.