RHSA-2021:0338 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. 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.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

• kernel: use-after-free in fs/block_dev.c (CVE-2020-15436)
• kernel: Nfsd failure to clear umask after processing an open or create (CVE-2020-35513)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Bug Fix(es):

• kernel-rt: update to the latest RHEL7.9.z3 source tree (BZ#1906133)
• [kernel-rt] WARNING: CPU: 8 PID: 586 at kernel/sched/core.c:3644 migrate_enable+0x15f/0x210 (BZ#1916123)
• [kernel-rt-debug] [ BUG: bad unlock balance detected! ] [RHEL-7.9.z] (BZ#1916130)

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.

Affected Products

• Red Hat Enterprise Linux for Real Time 7 x86_64
• Red Hat Enterprise Linux for Real Time for NFV 7 x86_64

Fixes

• BZ - 1901168 - CVE-2020-15436 kernel: use-after-free in fs/block_dev.c
• BZ - 1906133 - kernel-rt: update to the latest RHEL7.9.z3 source tree
• BZ - 1911309 - CVE-2020-35513 kernel: Nfsd failure to clear umask after processing an open or create

CVEs

• CVE-2020-15436
• CVE-2020-35513

References

• https://access.redhat.com/security/updates/classification/#moderate