RHSA-2021:1739HighCVSS 7.8

Red Hat Security Advisory: kernel-rt security and bug fix update

Published
May 18, 2021
Last Modified
November 6, 2026

🔗 CVE IDs covered (27)

CVE-2021-3428 →CVE-2023-1390 →CVE-2019-19528 →CVE-2020-0431 →CVE-2020-12114 →CVE-2020-12362 →CVE-2020-12464 →CVE-2020-25212 →CVE-2020-27835 →CVE-2021-0342 →CVE-2020-12364 →CVE-2020-14314 →CVE-2020-15437 →CVE-2020-25284 →CVE-2020-25285 →CVE-2020-25643 →CVE-2020-25704 →CVE-2020-27786 →CVE-2019-19523 →CVE-2020-11608 →CVE-2020-12363 →CVE-2020-14356 →CVE-2020-24394 →CVE-2020-28974 →CVE-2020-35508 →CVE-2020-36694 →CVE-2021-0605 →

📋 Description

CVE-2019-19523 — kernel: use-after-free caused by a malicious USB device in the drivers/usb/misc/adutux.c driver CVE-2019-19528 — kernel: use-after-free bug caused by a malicious USB device in the drivers/usb/misc/iowarrior.c driver CVE-2020-0431 — kernel: possible out of bounds write in kbd_keycode of keyboard.c CVE-2020-11608 — kernel: NULL pointer dereferences in ov511_mode_init_regs and ov518_mode_init_regs in drivers/media/usb/gspca/ov519.c CVE-2020-12114 — kernel: DoS by corrupting mountpoint reference counter CVE-2020-12362 — kernel: Integer overflow in Intel(R) Graphics Drivers CVE-2020-12363 — kernel: Improper input validation in some Intel(R) Graphics Drivers CVE-2020-12364 — kernel: Null pointer dereference in some Intel(R) Graphics Drivers CVE-2020-12464 — kernel: use-after-free in usb_sg_cancel function in drivers/usb/core/message.c CVE-2020-14314 — kernel: buffer uses out of index in ext3/4 filesystem CVE-2020-14356 — kernel: Use After Free vulnerability in cgroup BPF component CVE-2020-15437 — kernel: NULL pointer dereference in serial8250_isa_init_ports function in drivers/tty/serial/8250/8250_core.c CVE-2020-24394 — kernel: umask not applied on filesystem without ACL support CVE-2020-25212 — kernel: TOCTOU mismatch in the NFS client code CVE-2020-25284 — kernel: incomplete permission checking for access to rbd devices CVE-2020-25285 — kernel: race condition between hugetlb sysctl handlers in mm/hugetlb.c CVE-2020-25643 — kernel: improper input validation in ppp_cp_parse_cr function leads to memory corruption and read overflow CVE-2020-25704 — kernel: perf_event_parse_addr_filter memory CVE-2020-27786 — kernel: use-after-free in kernel midi subsystem CVE-2020-27835 — kernel: child process is able to access parent mm through hfi dev file handle CVE-2020-28974 — kernel: slab-out-of-bounds read in fbcon CVE-2020-35508 — kernel: fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parent CVE-2020-36694 — kernel: netfilter: use-after-free in the packet processing context CVE-2021-0342 — kernel: use after free in tun_get_user of tun.c could lead to local escalation of privilege CVE-2021-0605 — kernel: In pfkey_dump() dplen and splen can both be specified to access the xfrm_address_t structure out of bounds CVE-2021-3428 — kernel: integer overflow in ext4_es_cache_extent CVE-2023-1390 — kernel: remote DoS in TIPC kernel module

🎯 Affected products32

  • Red Hat Enterprise Linux Real Time (v. 8)
  • Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-0:4.18.0-305.rt7.72.el8.src as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-0:4.18.0-305.rt7.72.el8.src as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-core-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-core-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debug-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debug-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debug-core-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debug-core-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debug-kvm-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-devel-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-devel-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-kvm-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • kernel-rt-modules-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time (v. 8)
  • kernel-rt-modules-0:4.18.0-305.rt7.72.el8.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV (v. 8)
  • +2 more not shown

✅ Remediation

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. Workaround: As the system module will be auto-loaded when a device that uses the driver is attached (via USB), its use can be disabled by preventing the module from loading with the following instructions: # echo "install adutux /bin/true" >> /etc/modprobe.d/disable-adutux.conf The system will need to be restarted if the adutux module are loaded. In most circumstances, the kernel modules will be unable to be unloaded while any hardware is in use. If the system requires this module to work correctly, this mitigation may not be suitable. If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services. Workaround: This flaw can be mitigated by preventing the affected USB IO-Warrior driver (iowarrior) kernel module from loading during the boot time, ensure the module is added into the blacklist file. ~~~ Refer: How do I blacklist a kernel module to prevent it from loading automatically? https://access.redhat.com/solutions/41278 ~~~ Workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Workaround: In order to mitigate this issue it is possible to prevent the affected code from being loaded by blacklisting the kernel module gspca_ov519. For instructions relating to how to blacklist a kernel module refer to: https://access.redhat.com/solutions/41278 . Workaround: Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Workaround: If any directories of the partition (or image) broken, the command "e2fsck -Df .../partition-name" fixes it. Workaround: While there is no known mitigation to this flaw, configuring authentication and only mounting authenticated NFSv4 servers will significantly reduce the risk of this flaw being successfully exploited. Workaround: As the rbd module can be loaded by a priviledged user or process, its use can be disabled by preventing the module from loading with the following instructions: # echo "install rbd /bin/true" >> /etc/modprobe.d/disable-rdb.conf The system will need to be restarted if the modules isloaded. In most circumstances, the rbd kernel modules will be unable to be unloaded while in use. If the system requires this module to work correctly, (Such as a CEPH node) this mitigation may not be suitable. If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services. Workaround: To mitigate this issue, prevent modules hdlc_ppp, syncppp from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically. Workaround: As the midi module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions: # echo "install snd-rawmidi /bin/true" >> /etc/modprobe.d/disable-snd-rawmidi.conf The system will need to be restarted if the snd-rawmidi modules are loaded. In most circumstances, the CIFS kernel modules will be unable to be unloaded while any midi / sound devices are active and the protocol is in use. If the system requires this module to work correctly, this mitigation may not be suitable. If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services. Workaround: To mitigate this issue, prevent the module hfi1 from being loaded. Please see https://access.redhat.com/solutions/41278 for information on how to denylist a kernel module to prevent it from loading automatically. Workaround: Add 'nomodeset' option as kernel boot parameter to disable frame buffering in /etc/default/grub, and run 'grub2-mkconfig -o /boot/grub2/grub.cfg' and reboot. ~~~ # cat /proc/cmdline BOOT_IMAGE=(hd0,msdos1)/vmlinuz-4.18.0-147.el8.x86_64 root=/dev/mapper/rhel_rhel8u2--1-root ro crashkernel=auto resume=/dev/mapper/rhel_rhel8u2--1-swap rd.lvm.lv=rhel_rhel8u2-1/root rd.lvm.lv=rhel_rhel8u2-1/swap nomodeset # ls -l /dev/fb* ls: cannot access '/dev/fb*': No such file or directory ~~~ The above said mitigation does not so effect for rhel6 kernel , and is only applicable for rhel7/8. Workaround: In order to trigger the issue, it requires the ability to create user/net namespaces. On non-containerized deployments of Red Hat Enterprise Linux 8, you can disable user namespaces by setting user.max_user_namespaces to 0: # echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf # sysctl -p /etc/sysctl.d/userns.conf On containerized deployments such as Red Hat OpenShift Container Platform, do not use this mitigation as the functionality is needed to be enabled. Workaround: To mitigate this issue, prevent the module tun from being loaded. Please see https://access.redhat.com/solutions/41278 for information on how to blacklist a kernel module to prevent it from loading automatically. Workaround: If the CAP_NET_ADMIN capability is privileged by default (which is true for Red Hat Enterprise Linux 7), then only an otherwise privileged user can trigger this bug. On Red Hat Enterprise Linux 8 CAP_NET_ADMIN capability can be also gained by exploiting unprivileged user namespaces. The mitigation is to disable unprivileged user namespaces by setting user.max_user_namespaces to 0: # echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf # sysctl -p /etc/sysctl.d/userns.conf

🔗 References (29)