CVE-2009-1527 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2009-1527): Race condition in the ptrace_attach function in kernel/ptrace.c in the Linux kernel before 2.6.30-rc4 allows local users to gain privileges via a PTRACE_ATTACH ptrace call during an exec system call that is launching a setuid application, related to locking an incorrect cred_exec_mutex object.
note this allows for local root compromise: http://milw0rm.org/exploits/8673
This does not affect <2.6.29 (the code is different). I tried the exploit against 2.6.28.10 and it did not prevail. Eugene Teo, of Red Hat, said: "This vulnerability was introduced in commit d84f4f99 ("CRED: Inaugurate COW credentials"), and was fixed in commit cad81bc2 ("ptrace: ptrace_attach: fix the usage of ->cred_exec_mutex"). It affects kernel 2.6.29." Source: http://marc.info/?l=oss-security&m=124141149127926&w=2