The gnu regular expression code in file 4.20 allows context-dependent attackers to cause a denial of service (CPU consumption) via a crafted document with a large number of line feed characters, which is not well handled by OS/2 REXX regular expressions that use wildcards, as originally reported for AMaViS.
https://issues.rpath.com/browse/RPL-1311
https://bugs.gentoo.org/show_bug.cgi?id=174217
http://www.vupen.com/english/advisories/2007/2071
http://www.securityfocus.com/bid/24146
http://www.securityfocus.com/archive/1/469520/30/6420/threaded
http://www.mandriva.com/security/advisories?name=MDKSA-2007:114
http://www.gentoo.org/security/en/glsa/glsa-200704-13.xml
http://www.amavis.org/security/asa-2007-3.txt
http://secunia.com/advisories/25578
http://secunia.com/advisories/25544