[El-errata] New glibc updates available via Ksplice (ELSA-2021-4358)

[Errata Announcements for Oracle Linux]

Synopsis: ELSA-2021-4358 can now be patched using Ksplice
CVEs: CVE-2021-27645 CVE-2021-33574 CVE-2021-35942

Users with Oracle Linux Premier Support can now use Ksplice to patch
against the latest Oracle Linux Security Advisory, ELSA-2021-4358.

INSTALLING THE UPDATES

We recommend that all users of Ksplice on OL 8 install these updates.

You can install these updates by running:

# ksplice -y user upgrade

32-bit applications should be restarted after upgrading the on-disk
glibc RPMs and statically linked applications using
glibc should be rebuilt to include these fixes.

Ksplice user-space patching requires installation of Ksplice-aware
packages and the system must be rebooted after the first installation of
these packages.  Refer to the installation instructions for the Enhanced
Ksplice Client in the Ksplice User's Guide for more details.  Systems
may be prepared for Ksplice patching by installing the Ksplice aware
packages in advance, prior to installing the enhanced Ksplice client.

DESCRIPTION

* Note: Oracle will not provide a zero downtime update for CVE-2021-27645.

CVE-2021-27645 is a denial-of-service when  using the nameserver caching
daemon.


* CVE-2021-35942: Information leak when performing word expansion.

A logic error when performing word expansion using wordexp() could lead
to an invalid memory access or an information leak. A local attacker
could use this flow and crafted arguments to leak information and
facilitate an attack.


* CVE-2021-33574: Denial-of-service when using POSIX message queues.

A logic error when using mq_notify() function of POSIX message queues
could lead to a use-after-free. A local attacker could use this flaw to
cause a denial-of-service.

SUPPORT

Ksplice support is available at ksplice-support_ww at oracle.com.