Dan Rosenberg discovered several race condition vulnerabilities in fcrontab, part of the fcron scheduler, that could allow a local attacker to use symbolic links to read unauthorized files. If fcrontab is installed setuid root, an attacker can read arbitrary files, but when installed with its own group (i.e. 'fcron'), an attacker can only read other non-root users' crontabs and fcron configuration files. On Fedora, fcrontab is setuid fcron, which lessens the impact. Upstream has released fcron 3.0.5 to correct this issue.
fcron-3.0.5-1.fc13 has been submitted as an update for Fedora 13. http://admin.fedoraproject.org/updates/fcron-3.0.5-1.fc13
fcron-3.0.5-1.fc12 has been submitted as an update for Fedora 12. http://admin.fedoraproject.org/updates/fcron-3.0.5-1.fc12
fcron-3.0.5-1.fc12 has been pushed to the Fedora 12 stable repository. If problems still persist, please make note of it in this bug report.
fcron-3.0.5-1.fc13 has been pushed to the Fedora 13 stable repository. If problems still persist, please make note of it in this bug report.