The disconnect method in the Philips USB Webcam (pwc) driver in Linux kernel 2.6.x before 2.6.22.6 "relies on user space to close the device," which allows user-assisted local attackers to cause a denial of service (USB subsystem hang and CPU consumption in khubd) by not closing the device after the disconnect is invoked. NOTE: this rarely crosses privilege boundaries, unless the attacker can convince the victim to unplug the affected device.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10494
http://www.ubuntu.com/usn/usn-578-1
http://www.ubuntu.com/usn/usn-574-1
http://www.ubuntu.com/usn/usn-558-1
http://www.securityfocus.com/bid/25504
http://www.redhat.com/support/errata/RHSA-2008-0275.html
http://www.mandriva.com/security/advisories?name=MDVSA-2008:105
http://www.mandriva.com/security/advisories?name=MDVSA-2008:008
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.22.6
http://www.debian.org/security/2008/dsa-1504
http://www.debian.org/security/2008/dsa-1503
http://www.debian.org/security/2007/dsa-1381
http://secunia.com/advisories/32799
http://secunia.com/advisories/30294
http://secunia.com/advisories/29058
http://secunia.com/advisories/28971
http://secunia.com/advisories/28706
http://secunia.com/advisories/28170
http://secunia.com/advisories/26994
http://rhn.redhat.com/errata/RHSA-2008-0972.html