The wordwrap function in PHP 4 before 4.4.8, and PHP 5 before 5.2.4, does not properly use the breakcharlen variable, which allows remote attackers to cause a denial of service (divide-by-zero error and application crash, or infinite loop) via certain arguments, as demonstrated by a 'chr(0), 0, ""' argument set.
https://www.redhat.com/archives/fedora-package-announce/2007-September/msg00354.html
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10603
https://launchpad.net/bugs/173043
http://www.vupen.com/english/advisories/2007/3023
http://www.ubuntu.com/usn/usn-549-2
http://www.redhat.com/support/errata/RHSA-2007-0891.html
http://www.redhat.com/support/errata/RHSA-2007-0890.html
http://www.php.net/releases/5_2_4.php
http://www.php.net/ChangeLog-5.php#5.2.4
http://www.mandriva.com/security/advisories?name=MDKSA-2007:187
http://www.gentoo.org/security/en/glsa/glsa-200710-02.xml
http://www.debian.org/security/2008/dsa-1578
http://www.debian.org/security/2008/dsa-1444
http://support.avaya.com/elmodocs2/security/ASA-2007-449.htm
http://secweb.se/en/advisories/php-wordwrap-vulnerability/
http://secunia.com/advisories/30288
http://secunia.com/advisories/28658
http://secunia.com/advisories/28249
http://secunia.com/advisories/27864
http://secunia.com/advisories/27545
http://secunia.com/advisories/27377
http://secunia.com/advisories/27102
http://secunia.com/advisories/26967
http://secunia.com/advisories/26930
http://secunia.com/advisories/26895
http://secunia.com/advisories/26871
http://secunia.com/advisories/26838
http://secunia.com/advisories/26822
http://secunia.com/advisories/26642
http://rhn.redhat.com/errata/RHSA-2007-0889.html
http://lists.opensuse.org/opensuse-security-announce/2008-01/msg00006.html