Format string vulnerability in the rrdtool module 1.4.7 for Python, as used in Zenoss, allows context-dependent attackers to cause a denial of service (crash) via format string specifiers to the rrdtool.graph function.
https://github.com/oetiker/rrdtool-1.x/pull/397
https://github.com/oetiker/rrdtool-1.x/issues/396
https://bugzilla.redhat.com/show_bug.cgi?id=969296
http://www.openwall.com/lists/oss-security/2013/05/31/2