It was reported , that mwlib suffered from a flaw that could allow a remote attacker to perform a denial of service attack on a mwlib installation by forcing it to parse a specially-crafted #iferror magic function. This has been corrected  in upstream version 0.13.5.
Created python-mwlib tracking bugs for this issue
Affects: fedora-all [bug 800066]
Affects: epel-5 [bug 800067]
CVE request: http://www.openwall.com/lists/oss-security/2012/03/05/16