RHSA-2021:3987 - Security Advisory

Topic

An update for kernel is now available for Red Hat Enterprise Linux 7.7 Advanced Update Support, Red Hat Enterprise Linux 7.7 Telco Extended Update Support, and Red Hat Enterprise Linux 7.7 Update Services for SAP Solutions.

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.

Description

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

Security Fix(es):

• kernel: use-after-free in drivers/infiniband/core/ucma.c ctx use-after-free (CVE-2020-36385)
• kernel: Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks (CVE-2021-22543)
• kernel: powerpc: KVM guest OS users can cause host OS memory corruption (CVE-2021-37576)
• kernel: use-after-free in show_numa_stats function (CVE-2019-20934)
• kernel: SVM nested virtualization issue in KVM (AVIC support) (CVE-2021-3653)
• kernel: SVM nested virtualization issue in KVM (VMLOAD/VMSAVE) (CVE-2021-3656)

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):

• A race between i40e_ndo_set_vf_mac() and i40e_vsi_clear() in the i40e driver causes a use after free condition of the kmalloc-4096 slab cache. (BZ#1980333)

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 Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.7 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.7 x86_64

Fixes

• BZ - 1902788 - CVE-2019-20934 kernel: use-after-free in show_numa_stats function
• BZ - 1965461 - CVE-2021-22543 kernel: Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks
• BZ - 1974319 - CVE-2020-36385 kernel: use-after-free in drivers/infiniband/core/ucma.c ctx use-after-free
• BZ - 1983686 - CVE-2021-3653 kernel: SVM nested virtualization issue in KVM (AVIC support)
• BZ - 1983988 - CVE-2021-3656 kernel: SVM nested virtualization issue in KVM (VMLOAD/VMSAVE)
• BZ - 1986506 - CVE-2021-37576 kernel: powerpc: KVM guest OS users can cause host OS memory corruption

CVEs

• CVE-2019-20934
• CVE-2020-36385
• CVE-2021-3653
• CVE-2021-3656
• CVE-2021-22543
• CVE-2021-37576

References

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