CVE-2008-2664 ruby: Unsafe use of alloca in rb_str_format()

The rb_str_format function in Ruby 1.8.4 and earlier,
1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230,
1.8.7 before 1.8.7-p22, and 1.9.0 before 1.9.0-2 allows
context-dependent attackers to trigger memory corruption via
unspecified vectors related to alloca, a different issue than
CVE-2008-2662, CVE-2008-2663, and CVE-2008-2725.

NOTE: As of 20080624, there has been inconsistent usage of
multiple CVE identifiers related to Ruby. The CVE description
should be regarded as authoritative, although it is likely to change.