Integer signedness error in the vt console driver (formerly Newcons) in FreeBSD 9.3 before p10 and 10.1 before p6 allows local users to cause a denial of service (crash) and possibly gain privileges via a negative value in a VT_WAITACTIVE ioctl call, which triggers an array index error and out-of-bounds kernel memory access.

References

• https://nvd.nist.gov/vuln/detail/CVE-2014-0998
• https://www.freebsd.org/security/advisories/FreeBSD-EN-15:01.vt.asc
• http://seclists.org/fulldisclosure/2015/Jan/107
• http://www.coresecurity.com/advisories/freebsd-kernel-multiple-vulnerabilities
• http://www.securityfocus.com/archive/1/534563/100/0/threaded