Input validation error in Linux kernel - CVE-2020-27673

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Main Vulnerability Database Vulnerabilities #VU94154

Input validation error in Linux kernel - CVE-2020-27673

Published: October 22, 2020 / Updated: August 22, 2023


Vulnerability identifier: #VU94154
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2020-27673
CWE-ID: CWE-20
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to improper input validation within the clear_linked(), consume_one_event(), __evtchn_fifo_handle_events() and evtchn_fifo_percpu_init() functions in drivers/xen/events/events_fifo.c, within the module_param(), DEFINE_RWLOCK(), enable_dynirq(), notify_remote_via_irq(), EXPORT_SYMBOL_GPL(), xen_irq_init(), xen_free_irq(), xen_send_IPI_one(), __xen_evtchn_do_upcall(), xen_setup_callback_vector(), xen_evtchn_cpu_prepare() and xen_init_IRQ() functions in drivers/xen/events/events_base.c, within the active_evtchns() and evtchn_2l_handle_events() functions in drivers/xen/events/events_2l.c. A local user can perform a denial of service (DoS) attack.


Affected software

Linux kernel
Amazon Linux AMI
Gentoo Linux
SUSE CaaS Platform
SUSE Manager Server
SUSE Manager Retail Branch Server
SUSE Manager Proxy
SUSE Enterprise Storage
SUSE OpenStack Cloud Crowbar
SUSE OpenStack Cloud
HPE Helion Openstack
SUSE Linux Enterprise Server for SAP
SUSE Linux Enterprise High Availability
SUSE Linux Enterprise Server
SUSE Linux Enterprise Live Patching
SUSE Linux Enterprise Real Time Extension
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Module for Live Patching
SUSE Linux Enterprise Module for Basesystem
SUSE Linux Enterprise Module for Development Tools
SUSE Linux Enterprise Module for Legacy Software
SUSE Linux Enterprise Workstation Extension
SUSE Linux Enterprise Module for Public Cloud
openEuler
Ubuntu
Fedora
kernel-livepatch-4_12_14-150_72-default
kernel-livepatch-4_12_14-150_72-default-debuginfo
kernel-livepatch-4_12_14-197_89-default
kgraft-patch-4_4_180-94_144-default-debuginfo
kgraft-patch-4_4_180-94_144-default
kgraft-patch-4_12_14-95_74-default
kernel-livepatch-5_3_18-59_5-default
kernel-livepatch-5_3_18-59_5-default-debuginfo
kernel-livepatch-SLE15-SP3_Update_1-debugsource
gfs2-kmp-default-debuginfo
gfs2-kmp-default
dlm-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
ocfs2-kmp-default
dlm-kmp-default
cluster-md-kmp-default-debuginfo
cluster-md-kmp-default
kernel-default-man
kernel-source
kernel-macros
kernel-devel
kernel-syms
kernel-default-kgraft
kernel-default-devel
kernel-default-debugsource
kernel-default-debuginfo
kernel-default-base-debuginfo
kernel-default-base
kernel-default
cluster-md-kmp-rt-debuginfo
kernel-source-rt
dlm-kmp-rt
dlm-kmp-rt-debuginfo
gfs2-kmp-rt
gfs2-kmp-rt-debuginfo
kernel-rt
kernel-rt-base
kernel-rt-base-debuginfo
kernel-rt-debuginfo
kernel-rt-debugsource
kernel-rt-devel
kernel-rt_debug
kernel-rt-devel-debuginfo
cluster-md-kmp-rt
kernel-devel-rt
ocfs2-kmp-rt-debuginfo
ocfs2-kmp-rt
kernel-syms-rt
kernel-rt_debug-devel-debuginfo
kernel-rt_debug-devel
kernel-rt_debug-debugsource
kernel-rt_debug-debuginfo
kernel-default-kgraft-devel
kernel-default-devel-debuginfo
reiserfs-kmp-default-debuginfo
reiserfs-kmp-default
kernel-vanilla-debugsource
kernel-vanilla-debuginfo
kernel-vanilla-base-debuginfo
kernel-vanilla-base
kernel-obs-build-debugsource
kernel-obs-build
kernel-default-livepatch
kernel-zfcpdump-debugsource
kernel-zfcpdump-debuginfo
kernel-docs
kernel-default-livepatch-devel
app-emulation/xen
app-emulation/xen-tools
kernel
python2-perf
python3-perf-debuginfo
bpftool-debuginfo
perf-debuginfo
kernel-debuginfo
kernel-tools
kernel-debugsource
bpftool
python3-perf
kernel-tools-devel
kernel-tools-debuginfo
python2-perf-debuginfo
perf
kernel-azure
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure-devel
kernel-azure-devel-debuginfo
kernel-syms-azure
kernel-devel-azure
kernel-source-azure
kernel-preempt-devel-debuginfo
kernel-zfcpdump
kernel-preempt-devel
kernel-preempt-extra-debuginfo
kernel-preempt-extra
kernel-preempt-debugsource
kernel-default-extra-debuginfo
kernel-64kb-devel-debuginfo
kernel-64kb-devel
kernel-64kb-debugsource
kernel-64kb-debuginfo
kernel-64kb
kernel-preempt
kernel-preempt-debuginfo
kernel-default-extra
linux-image-virtual (Ubuntu package)
linux-image-generic (Ubuntu package)
linux-image-oem-20.04 (Ubuntu package)
linux-image-lowlatency (Ubuntu package)
linux-image-generic-lpae (Ubuntu package)
linux-image-generic-64k (Ubuntu package)
linux-image-5.8.0-44-generic-64k (Ubuntu package)
linux-image-5.8.0-44-lowlatency (Ubuntu package)
linux-image-5.8.0-44-generic-lpae (Ubuntu package)
linux-image-5.8.0-44-generic (Ubuntu package)
linux-image-generic-64k-hwe-20.04 (Ubuntu package)
linux-image-generic-hwe-20.04 (Ubuntu package)
linux-image-generic-lpae-hwe-20.04 (Ubuntu package)
linux-image-lowlatency-hwe-20.04 (Ubuntu package)
linux-image-virtual-hwe-20.04 (Ubuntu package)
linux-image-raspi (Ubuntu package)
linux-image-5.8.0-1016-raspi (Ubuntu package)
linux-image-5.8.0-1016-raspi-nolpae (Ubuntu package)
linux-image-raspi-nolpae (Ubuntu package)
linux-image-kvm (Ubuntu package)
linux-image-5.8.0-1019-kvm (Ubuntu package)
linux-image-oracle (Ubuntu package)
linux-image-5.8.0-1021-oracle (Ubuntu package)
linux-image-azure (Ubuntu package)
linux-image-gcp (Ubuntu package)
linux-image-gke (Ubuntu package)
linux-image-5.8.0-1023-gcp (Ubuntu package)
linux-image-5.8.0-1023-azure (Ubuntu package)
linux-image-5.8.0-1024-aws (Ubuntu package)
linux-image-aws (Ubuntu package)
kernel-headers

How to mitigate CVE-2020-27673

Install update from vendor's website.

kernel-livepatch-4_12_14-150_72-default - update to 1-1.3.1
kernel-livepatch-4_12_14-150_72-default-debuginfo - update to 1-1.3.1
kernel-livepatch-4_12_14-197_89-default - update to 1-3.3.2
kgraft-patch-4_4_180-94_144-default-debuginfo - update to 1-4.3.1
kgraft-patch-4_4_180-94_144-default - update to 1-4.3.1
kgraft-patch-4_12_14-95_74-default - update to 1-6.3.1
kernel-livepatch-5_3_18-59_5-default - update to 1-7.5.1
kernel-livepatch-5_3_18-59_5-default-debuginfo - update to 1-7.5.1
kernel-livepatch-SLE15-SP3_Update_1-debugsource - update to 1-7.5.1
gfs2-kmp-default-debuginfo - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
gfs2-kmp-default - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
dlm-kmp-default-debuginfo - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
ocfs2-kmp-default-debuginfo - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
ocfs2-kmp-default - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
dlm-kmp-default - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
cluster-md-kmp-default-debuginfo - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
cluster-md-kmp-default - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-default-man - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2
kernel-source - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-macros - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-devel - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-syms - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.1
kernel-default-kgraft - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1
kernel-default-devel - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-default-debugsource - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-default-debuginfo - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-default-base-debuginfo - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-197.89.2
kernel-default-base - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2.18.2.2
kernel-default - addressed in versions 4.4.180-94.144.1, 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
cluster-md-kmp-rt-debuginfo - update to 4.12.14-10.37.1
kernel-source-rt - update to 4.12.14-10.37.1
dlm-kmp-rt - update to 4.12.14-10.37.1
dlm-kmp-rt-debuginfo - update to 4.12.14-10.37.1
gfs2-kmp-rt - update to 4.12.14-10.37.1
gfs2-kmp-rt-debuginfo - update to 4.12.14-10.37.1
kernel-rt - update to 4.12.14-10.37.1
kernel-rt-base - update to 4.12.14-10.37.1
kernel-rt-base-debuginfo - update to 4.12.14-10.37.1
kernel-rt-debuginfo - update to 4.12.14-10.37.1
kernel-rt-debugsource - update to 4.12.14-10.37.1
kernel-rt-devel - update to 4.12.14-10.37.1
kernel-rt_debug - update to 4.12.14-10.37.1
kernel-rt-devel-debuginfo - update to 4.12.14-10.37.1
cluster-md-kmp-rt - update to 4.12.14-10.37.1
kernel-devel-rt - update to 4.12.14-10.37.1
ocfs2-kmp-rt-debuginfo - update to 4.12.14-10.37.1
ocfs2-kmp-rt - update to 4.12.14-10.37.1
kernel-syms-rt - update to 4.12.14-10.37.1
kernel-rt_debug-devel-debuginfo - update to 4.12.14-10.37.1
kernel-rt_debug-devel - update to 4.12.14-10.37.1
kernel-rt_debug-debugsource - update to 4.12.14-10.37.1
kernel-rt_debug-debuginfo - update to 4.12.14-10.37.1
kernel-default-kgraft-devel - update to 4.12.14-95.74.1
kernel-default-devel-debuginfo - addressed in versions 4.12.14-95.74.1, 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
reiserfs-kmp-default-debuginfo - addressed in versions 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
reiserfs-kmp-default - addressed in versions 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-vanilla-debugsource - update to 4.12.14-150.72.1
kernel-vanilla-debuginfo - update to 4.12.14-150.72.1
kernel-vanilla-base-debuginfo - update to 4.12.14-150.72.1
kernel-vanilla-base - update to 4.12.14-150.72.1
kernel-obs-build-debugsource - addressed in versions 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.1
kernel-obs-build - addressed in versions 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.1
kernel-default-livepatch - addressed in versions 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-zfcpdump-debugsource - addressed in versions 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-zfcpdump-debuginfo - addressed in versions 4.12.14-150.72.1, 4.12.14-197.89.2, 5.3.18-59.5.2
kernel-docs - addressed in versions 4.12.14-150.72.2, 4.12.14-197.89.3, 5.3.18-59.5.2
kernel-default-livepatch-devel - addressed in versions 4.12.14-197.89.2, 5.3.18-59.5.2
app-emulation/xen - update to 4.13.2
app-emulation/xen-tools - update to 4.13.2
kernel - update to 4.14.209-117.337
python2-perf - update to 4.19.90-2011.6.0.0049
python3-perf-debuginfo - update to 4.19.90-2011.6.0.0049
bpftool-debuginfo - update to 4.19.90-2011.6.0.0049
perf-debuginfo - update to 4.19.90-2011.6.0.0049
kernel-debuginfo - update to 4.19.90-2011.6.0.0049
kernel-tools - update to 4.19.90-2011.6.0.0049
kernel-debugsource - update to 4.19.90-2011.6.0.0049
bpftool - update to 4.19.90-2011.6.0.0049
kernel - update to 4.19.90-2011.6.0.0049
python3-perf - update to 4.19.90-2011.6.0.0049
kernel-tools-devel - update to 4.19.90-2011.6.0.0049
kernel-devel - update to 4.19.90-2011.6.0.0049
kernel-tools-debuginfo - update to 4.19.90-2011.6.0.0049
python2-perf-debuginfo - update to 4.19.90-2011.6.0.0049
kernel-source - update to 4.19.90-2011.6.0.0049
perf - update to 4.19.90-2011.6.0.0049
kernel-azure - update to 5.3.18-38.3.1
kernel-azure-debuginfo - update to 5.3.18-38.3.1
kernel-azure-debugsource - update to 5.3.18-38.3.1
kernel-azure-devel - update to 5.3.18-38.3.1
kernel-azure-devel-debuginfo - update to 5.3.18-38.3.1
kernel-syms-azure - update to 5.3.18-38.3.1
kernel-devel-azure - update to 5.3.18-38.3.1
kernel-source-azure - update to 5.3.18-38.3.1
kernel-preempt-devel-debuginfo - update to 5.3.18-59.5.2
kernel-zfcpdump - update to 5.3.18-59.5.2
kernel-preempt-devel - update to 5.3.18-59.5.2
kernel-preempt-extra-debuginfo - update to 5.3.18-59.5.2
kernel-preempt-extra - update to 5.3.18-59.5.2
kernel-preempt-debugsource - update to 5.3.18-59.5.2
kernel-default-extra-debuginfo - update to 5.3.18-59.5.2
kernel-64kb-devel-debuginfo - update to 5.3.18-59.5.2
kernel-64kb-devel - update to 5.3.18-59.5.2
kernel-64kb-debugsource - update to 5.3.18-59.5.2
kernel-64kb-debuginfo - update to 5.3.18-59.5.2
kernel-64kb - update to 5.3.18-59.5.2
kernel-preempt - update to 5.3.18-59.5.2
kernel-preempt-debuginfo - update to 5.3.18-59.5.2
kernel-default-extra - update to 5.3.18-59.5.2
linux-image-virtual (Ubuntu package) - update to 5.8.0.44.49
linux-image-generic (Ubuntu package) - update to 5.8.0.44.49
linux-image-oem-20.04 (Ubuntu package) - update to 5.8.0.44.49
linux-image-lowlatency (Ubuntu package) - update to 5.8.0.44.49
linux-image-generic-lpae (Ubuntu package) - update to 5.8.0.44.49
linux-image-generic-64k (Ubuntu package) - update to 5.8.0.44.49
linux-image-5.8.0-44-generic-64k (Ubuntu package) - update to 5.8.0-44.50
linux-image-5.8.0-44-lowlatency (Ubuntu package) - update to 5.8.0-44.50~20.04.1
linux-image-5.8.0-44-generic-lpae (Ubuntu package) - update to 5.8.0-44.50~20.04.1
linux-image-5.8.0-44-generic (Ubuntu package) - update to 5.8.0-44.50~20.04.1
linux-image-generic-64k-hwe-20.04 (Ubuntu package) - update to 5.8.0.44.50~20.04.30
linux-image-generic-hwe-20.04 (Ubuntu package) - update to 5.8.0.44.50~20.04.30
linux-image-generic-lpae-hwe-20.04 (Ubuntu package) - update to 5.8.0.44.50~20.04.30
linux-image-lowlatency-hwe-20.04 (Ubuntu package) - update to 5.8.0.44.50~20.04.30
linux-image-virtual-hwe-20.04 (Ubuntu package) - update to 5.8.0.44.50~20.04.30
linux-image-raspi (Ubuntu package) - update to 5.8.0.1016.19
linux-image-5.8.0-1016-raspi (Ubuntu package) - update to 5.8.0-1016.19
linux-image-5.8.0-1016-raspi-nolpae (Ubuntu package) - update to 5.8.0-1016.19
linux-image-raspi-nolpae (Ubuntu package) - update to 5.8.0.1016.19
linux-image-kvm (Ubuntu package) - update to 5.8.0.1019.21
linux-image-5.8.0-1019-kvm (Ubuntu package) - update to 5.8.0-1019.21
linux-image-oracle (Ubuntu package) - update to 5.8.0.1021.20
linux-image-5.8.0-1021-oracle (Ubuntu package) - update to 5.8.0-1021.22
linux-image-azure (Ubuntu package) - update to 5.8.0.1023.23
linux-image-gcp (Ubuntu package) - update to 5.8.0.1023.23
linux-image-gke (Ubuntu package) - update to 5.8.0.1023.23
linux-image-5.8.0-1023-gcp (Ubuntu package) - update to 5.8.0-1023.24
linux-image-5.8.0-1023-azure (Ubuntu package) - update to 5.8.0-1023.25
linux-image-5.8.0-1024-aws (Ubuntu package) - update to 5.8.0-1024.26
linux-image-aws (Ubuntu package) - update to 5.8.0.1024.26
kernel-headers - addressed in versions 5.9.7-100.fc32, 5.9.7-200.fc33
kernel-tools - addressed in versions 5.9.7-100.fc32, 5.9.7-200.fc33
kernel - addressed in versions 5.9.8-100.fc32, 5.9.8-200.fc33

External References

Related Security Bulletins