A flaw was found in the way Pidgin's PurpleCircBuffer object is expanded. If the buffer is full when more data arrives, it results in corruption of the data stored in the buffer. This corrupt data could possibly result in confusing or misleading data being presented to the user, or possibly crash Pidgin.
Link to upstream advisory: http://www.pidgin.im/news/security//?id=31
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Red Hat Enterprise Linux 5 Via RHSA-2009:1060 https://rhn.redhat.com/errata/RHSA-2009-1060.html
pidgin-2.5.6-1.fc9 has been submitted as an update for Fedora 9. http://admin.fedoraproject.org/updates/pidgin-2.5.6-1.fc9
pidgin-2.5.6-1.fc9 has been pushed to the Fedora 9 stable repository. If problems still persist, please make note of it in this bug report.
pidgin-2.5.6-1.fc11 has been pushed to the Fedora 11 stable repository. If problems still persist, please make note of it in this bug report.
pidgin-2.5.6-1.fc10 has been pushed to the Fedora 10 stable repository. If problems still persist, please make note of it in this bug report.
This issue was addressed in: Red Hat Enterprise Linux: http://rhn.redhat.com/errata/RHSA-2009-1060.html Fedora: https://admin.fedoraproject.org/updates/F10/FEDORA-2009-5597 https://admin.fedoraproject.org/updates/F11/FEDORA-2009-5583 https://admin.fedoraproject.org/updates/F9/FEDORA-2009-5552