A Red Hat Security Advisory RHSA-2012:0103 for squirrelmail packages shipped in Red Hat Enterprise Linux 4 and 5 claim to have fixed CVE-2010-2813 issue ("CVE-2010-2813 SquirrelMail: DoS (disk space consumption) by random IMAP login attempts with 8-bit characters in the password", bug #618096). However, the patch for this issue was not applied correctly and hence the issue was not fixed as stated in the advisory.
CVE assignment notification: http://www.openwall.com/lists/oss-security/2012/04/20/22
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Via RHSA-2013:0126 https://rhn.redhat.com/errata/RHSA-2013-0126.html