Serious Linux Security Holes Uncovered and Patched:
"The Polish security non-profit organization iSEC Security Research on Wednesday released an advisory describing two 'critical security vulnerabilities' in Linux 2.4 and 2.6's 'kernel-memory-management code inside the 'mremap(2)' system call.… "

http://www.eweek.com/article2/0,4149,1530875,00.asp