RHSA-2021:1288HighCVSS 7.8

Red Hat Security Advisory: kernel security and bug fix update

Published
April 20, 2021
Last Modified
July 30, 2026

🔗 CVE IDs covered (4)

CVE-2020-29661 →CVE-2021-20265 →CVE-2021-27364 →CVE-2021-27365 →

📋 Description

CVE-2020-29661 — kernel: locking issue in drivers/tty/tty_jobctrl.c can lead to an use-after-free CVE-2021-20265 — kernel: increase slab leak leads to DoS CVE-2021-27364 — kernel: out-of-bounds read in libiscsi module CVE-2021-27365 — kernel: heap buffer overflow in the iSCSI subsystem

🎯 Affected products58

  • Red Hat Enterprise Linux Server (v. 6 ELS)
  • Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-0:2.6.32-754.39.1.el6.src as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-abi-whitelists-0:2.6.32-754.39.1.el6.noarch as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-debuginfo-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-debuginfo-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debug-debuginfo-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-debuginfo-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debug-debuginfo-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-debuginfo-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debug-devel-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-devel-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debug-devel-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debuginfo-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debuginfo-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debuginfo-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debuginfo-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debuginfo-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debuginfo-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debuginfo-common-i686-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debuginfo-common-i686-0:2.6.32-754.39.1.el6.i686 as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debuginfo-common-s390x-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • kernel-debuginfo-common-s390x-0:2.6.32-754.39.1.el6.s390x as a component of Red Hat Enterprise Linux Server Optional (v. 6 ELS)
  • kernel-debuginfo-common-x86_64-0:2.6.32-754.39.1.el6.x86_64 as a component of Red Hat Enterprise Linux Server (v. 6 ELS)
  • +28 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: Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible. 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: The LIBISCSI module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions: # echo "install libiscsi /bin/true" >> /etc/modprobe.d/disable-libiscsi.conf The system will need to be restarted if the libiscsi modules are loaded. In most circumstances, the libiscsi kernel modules will be unable to be unloaded while any network interfaces are active and the protocol is in use. If the system requires iscsi 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: The LIBISCSI module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions: ~~~ # echo "install libiscsi /bin/true" >> /etc/modprobe.d/disable-libiscsi.conf ~~~ The system will need to be restarted if the libiscsi modules are loaded. In most circumstances, the libiscsi kernel modules will be unable to be unloaded while any network interfaces are active and the protocol is in use. If the system requires iscsi 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.

🔗 References (7)