The Linux kernel 2.6 before 2.6.12.1 allows local users to cause a denial of service (kernel panic) via a non group-leader thread executing a different program than was pending in itimer, which causes the signal to be delivered to the old group-leader task, which does not exist.

References

• https://nvd.nist.gov/vuln/detail/CVE-2005-1913
• https://exchange.xforce.ibmcloud.com/vulnerabilities/21138
• http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.12.1
• http://www.securityfocus.com/bid/14054
• http://www.ubuntu.com/usn/usn-178-1
• http://secunia.com/advisories/15786