pango -- integer overflow

oCERT reports:

Pango suffers from a multiplicative integer overflow which
may lead to a potentially exploitable, heap overflow depending
on the calling conditions.
For example, this vulnerability is remotely reachable in Firefox
by creating an overly large document.location value but only results
in a process-terminating, allocation error (denial of service).
The affected function is pango_glyph_string_set_size. An overflow
check when doubling the size neglects the overflow possible on the
subsequent allocation.