CVE 2007-2953
Format string vulnerability in the helptags_one function in src/ex_cmds.c in Vim 6.4 and earlier, and 7.x up to 7.1, allows user-assisted remote attackers to execute arbitrary code via format string specifiers in a help-tags tag in a help file, related to the helptags command.
See the 
CVE page on Mitre.org
for more details.
