Kernel 2.4.23 & 2.6.x local root exploitable :)

[N.B.]

Hello ...

you should update your kernel as soon as possible. Not seens any cook book exploits in the wild yet, but ...

http://www.kernel.org/pub/linux/kernel/v2.4/ChangeLog-2.4.24
Andrea Arcangeli: malicious users of mremap() syscall can gain priviledges

No patch for 2.6 yet