CVE-2007-4990
The swap_char2b function in X.Org X Font Server (xfs) before 1.0.5 allows context-dependent attackers to execute arbitrary code via (1) QueryXBitmaps and (2) QueryXExtents protocol requests with crafted size values that specify an arbitrary number of bytes to be swapped on the heap, which triggers heap corruption.
Date published : 2007-10-05
http://lists.apple.com/archives/security-announce/2008/Mar/msg00001.html