Some vulnerabilities and a weakness have been reported in the Linux Kernel, which can be exploited by malicious, local users to disclose potentially sensitive information and malicious people to cause a DoS (Denial of Service).

1) A NULL-pointer dereference exists within netfilter when handling new SCTP connections with unknown chunk types. This can be exploited to crash the kernel by sending malicious packets.

Note: This issue is reintroduced in version 2.6.22.

2) An underflow error within the "cpuset_task_read()" function in /kernel/cpuset.c can be exploited to read kernel memory, which may contain potentially sensitive information.

Successful exploitation requires that the attacker has access to open the /dev/cpuset/tasks file (the cpuset file system needs to be mounted).

3) The kernel does not handle seeds for the random number generator correctly. This may weaken the security of applications relying on the randomness of the kernel random number generator.

4) A vulnerability is caused due to an error within the function "tcp_accept_from_sock()" in fs/dlm/lowcomms.c. This can be exploited to halt services using the DLM by opening a connection to the DLM port (default 21064/TCP).

Successful exploitation requires that DLM is used and an attacker can create TCP connections to said port.

Solution
Update to version 2.6.20.13 or 2.6.21.4
Further details available to Secunia VIM customers

Provided and/or discovered by
1) Vilmos Nebehaj
2) Discovered by an anonymous person and reported via iDefense Labs.
3) Reported by the vendor.
4) Reported in a Red Hat Bugzilla report.

Changelog
Further details available to Secunia VIM customers

Original Advisory
Kernel:
http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.21.4
http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.22.1

iDefense Labs:
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=541

Red Hat:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=245922

Deep Links
Links available to Secunia VIM customers