7.2 - RHSA-2017:0986

Problem Description:

An update for kernel is now available for Red Hat Enterprise Linux 6.4 Advanced Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Server AUS (v. 6.4) - noarch, x86_64 Red Hat Enterprise Linux Server Optional AUS (v. 6.4) - x86_64

3. Description:

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

* A race condition flaw was found in the N_HLDC Linux kernel driver when accessing n_hdlc.tbuf list that can lead to double free. A local, unprivileged user able to set the HDLC line discipline on the tty device could use this flaw to increase their privileges on the system. (CVE-2017-2636, Important)

Red Hat would like to thank Alexander Popov for reporting this issue.

4. Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

5. Bugs fixed (https://bugzilla.redhat.com/):

1428319 - CVE-2017-2636 kernel: Race condition access to n_hdlc.tbuf causes double free in n_hdlc_release()