Use-after-free in Linux kernel - CVE-2020-25668

Vulnerability identifier: #VU83431

CSH Severity: Low

CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2020-25668

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local authenticated user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the con_font_op. A local authenticated user can trigger a use-after-free error and escalate privileges on the system.

Linux kernel
Amazon Linux AMI
Anolis OS
Ubuntu
openEuler
Fedora
linux-image-virtual-lts-xenial (Ubuntu package)
linux-image-powerpc64-smp-lts-xenial (Ubuntu package)
linux-image-powerpc64-emb-lts-xenial (Ubuntu package)
linux-image-powerpc-smp-lts-xenial (Ubuntu package)
linux-image-powerpc-e500mc-lts-xenial (Ubuntu package)
linux-image-lowlatency-lts-xenial (Ubuntu package)
linux-image-generic-lts-xenial (Ubuntu package)
linux-image-generic-lpae-lts-xenial (Ubuntu package)
linux-image-powerpc64-smp (Ubuntu package)
linux-image-lowlatency (Ubuntu package)
linux-image-generic-lpae (Ubuntu package)
linux-image-generic (Ubuntu package)
linux-image-powerpc-e500mc (Ubuntu package)
linux-image-powerpc-smp (Ubuntu package)
linux-image-powerpc64-emb (Ubuntu package)
linux-image-virtual (Ubuntu package)
linux-image-4.4.0-198-powerpc64-smp (Ubuntu package)
linux-image-4.4.0-198-generic (Ubuntu package)
linux-image-4.4.0-198-generic-lpae (Ubuntu package)
linux-image-4.4.0-198-lowlatency (Ubuntu package)
linux-image-4.4.0-198-powerpc-e500mc (Ubuntu package)
linux-image-4.4.0-198-powerpc-smp (Ubuntu package)
linux-image-4.4.0-198-powerpc64-emb (Ubuntu package)
linux-image-aws (Ubuntu package)
linux-image-4.4.0-1083-aws (Ubuntu package)
linux-image-kvm (Ubuntu package)
linux-image-4.4.0-1085-kvm (Ubuntu package)
linux-image-4.4.0-1119-aws (Ubuntu package)
linux-image-raspi2 (Ubuntu package)
linux-image-4.4.0-1143-raspi2 (Ubuntu package)
linux-image-snapdragon (Ubuntu package)
linux-image-4.4.0-1147-snapdragon (Ubuntu package)
kernel
linux-image-virtual-hwe-16.04 (Ubuntu package)
linux-image-oem (Ubuntu package)
linux-image-lowlatency-hwe-16.04 (Ubuntu package)
linux-image-generic-lpae-hwe-16.04 (Ubuntu package)
linux-image-generic-hwe-16.04 (Ubuntu package)
linux-image-4.15.0-129-generic-lpae (Ubuntu package)
linux-image-4.15.0-129-lowlatency (Ubuntu package)
linux-image-4.15.0-129-generic (Ubuntu package)
linux-image-oracle (Ubuntu package)
linux-image-4.15.0-1062-oracle (Ubuntu package)
linux-image-oracle-lts-18.04 (Ubuntu package)
linux-image-gke-4.15 (Ubuntu package)
linux-image-gke (Ubuntu package)
linux-image-4.15.0-1077-gke (Ubuntu package)
linux-image-4.15.0-1077-raspi2 (Ubuntu package)
linux-image-4.15.0-1082-kvm (Ubuntu package)
linux-image-aws-hwe (Ubuntu package)
linux-image-gcp (Ubuntu package)
linux-image-aws-lts-18.04 (Ubuntu package)
linux-image-4.15.0-1091-aws (Ubuntu package)
linux-image-4.15.0-1091-gcp (Ubuntu package)
linux-image-gcp-lts-18.04 (Ubuntu package)
linux-image-4.15.0-1094-snapdragon (Ubuntu package)
linux-image-azure-lts-18.04 (Ubuntu package)
linux-image-azure (Ubuntu package)
linux-image-4.15.0-1103-azure (Ubuntu package)
kernel-debuginfo
kernel-tools
kernel-debugsource
bpftool
perf-debuginfo
kernel-source
perf
python3-perf-debuginfo
python2-perf
python3-perf
bpftool-debuginfo
kernel-tools-devel
kernel-devel
kernel-tools-debuginfo
python2-perf-debuginfo
kernel-tools-libs
python-perf
kernel-tools-libs-devel
kernel-headers
kernel-debug-devel
kernel-debug
linux-image-oem-osp1 (Ubuntu package)
linux-image-5.4.0-59-lowlatency (Ubuntu package)
linux-image-5.4.0-59-generic (Ubuntu package)
linux-image-5.4.0-59-generic-lpae (Ubuntu package)
linux-image-virtual-hwe-18.04 (Ubuntu package)
linux-image-snapdragon-hwe-18.04 (Ubuntu package)
linux-image-lowlatency-hwe-18.04 (Ubuntu package)
linux-image-generic-lpae-hwe-18.04 (Ubuntu package)
linux-image-generic-hwe-18.04 (Ubuntu package)
linux-image-5.4.0-1026-raspi (Ubuntu package)
linux-image-raspi-hwe-18.04 (Ubuntu package)
linux-image-raspi (Ubuntu package)
linux-image-5.4.0-1031-kvm (Ubuntu package)
linux-image-5.4.0-1033-gcp (Ubuntu package)
linux-image-5.4.0-1033-gke (Ubuntu package)
linux-image-gke-5.4 (Ubuntu package)
linux-image-5.4.0-1034-aws (Ubuntu package)
linux-image-5.4.0-1034-oracle (Ubuntu package)
linux-image-5.4.0-1035-azure (Ubuntu package)
linux-image-oem-20.04 (Ubuntu package)
linux-image-generic-64k (Ubuntu package)
linux-image-5.8.0-44-generic-64k (Ubuntu package)
linux-image-5.8.0-44-generic (Ubuntu package)
linux-image-5.8.0-44-generic-lpae (Ubuntu package)
linux-image-5.8.0-44-lowlatency (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-generic-64k-hwe-20.04 (Ubuntu package)
linux-image-generic-hwe-20.04 (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-5.8.0-1019-kvm (Ubuntu package)
linux-image-5.8.0-1021-oracle (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)

Install update from vendor's website.

Linux kernel - update to 4.4.242
linux-image-virtual-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-powerpc64-smp-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-powerpc64-emb-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-powerpc-smp-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-powerpc-e500mc-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-lowlatency-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-generic-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-generic-lpae-lts-xenial (Ubuntu package) - update to 4.4.0.198.173
linux-image-powerpc64-smp (Ubuntu package) - update to 4.4.0.198.204
linux-image-lowlatency (Ubuntu package) - addressed in versions 4.4.0.198.204, 4.15.0.129.116, 5.4.0.59.62, 5.8.0.44.49
linux-image-generic-lpae (Ubuntu package) - addressed in versions 4.4.0.198.204, 4.15.0.129.116, 5.4.0.59.62, 5.8.0.44.49
linux-image-generic (Ubuntu package) - addressed in versions 4.4.0.198.204, 4.15.0.129.116, 5.4.0.59.62, 5.8.0.44.49
linux-image-powerpc-e500mc (Ubuntu package) - update to 4.4.0.198.204
linux-image-powerpc-smp (Ubuntu package) - update to 4.4.0.198.204
linux-image-powerpc64-emb (Ubuntu package) - update to 4.4.0.198.204
linux-image-virtual (Ubuntu package) - addressed in versions 4.4.0.198.204, 4.15.0.129.116, 5.4.0.59.62, 5.8.0.44.49
linux-image-4.4.0-198-powerpc64-smp (Ubuntu package) - update to 4.4.0-198.230~14.04.1
linux-image-4.4.0-198-generic (Ubuntu package) - update to 4.4.0-198.230~14.04.1
linux-image-4.4.0-198-generic-lpae (Ubuntu package) - update to 4.4.0-198.230~14.04.1
linux-image-4.4.0-198-lowlatency (Ubuntu package) - update to 4.4.0-198.230~14.04.1
linux-image-4.4.0-198-powerpc-e500mc (Ubuntu package) - update to 4.4.0-198.230~14.04.1
linux-image-4.4.0-198-powerpc-smp (Ubuntu package) - update to 4.4.0-198.230~14.04.1
linux-image-4.4.0-198-powerpc64-emb (Ubuntu package) - update to 4.4.0-198.230~14.04.1
linux-image-aws (Ubuntu package) - addressed in versions 4.4.0.1083.80, 4.4.0.1119.124, 5.4.0.1034.19, 5.4.0.1034.35, 5.8.0.1024.26
linux-image-4.4.0-1083-aws (Ubuntu package) - update to 4.4.0-1083.87
linux-image-kvm (Ubuntu package) - addressed in versions 4.4.0.1085.83, 4.15.0.1082.78, 5.4.0.1031.29, 5.8.0.1019.21
linux-image-4.4.0-1085-kvm (Ubuntu package) - update to 4.4.0-1085.94
linux-image-4.4.0-1119-aws (Ubuntu package) - update to 4.4.0-1119.133
linux-image-raspi2 (Ubuntu package) - addressed in versions 4.4.0.1143.143, 4.15.0.1077.74, 5.4.0.1026.61
linux-image-4.4.0-1143-raspi2 (Ubuntu package) - update to 4.4.0-1143.153
linux-image-snapdragon (Ubuntu package) - addressed in versions 4.4.0.1147.139, 4.15.0.1094.97
linux-image-4.4.0-1147-snapdragon (Ubuntu package) - update to 4.4.0-1147.157
kernel - update to 4.14.209-117.337
linux-image-virtual-hwe-16.04 (Ubuntu package) - update to 4.15.0.129.128
linux-image-oem (Ubuntu package) - addressed in versions 4.15.0.129.128, 5.4.0.59.62, 5.4.0.59.65~18.04.54
linux-image-lowlatency-hwe-16.04 (Ubuntu package) - update to 4.15.0.129.128
linux-image-generic-lpae-hwe-16.04 (Ubuntu package) - update to 4.15.0.129.128
linux-image-generic-hwe-16.04 (Ubuntu package) - update to 4.15.0.129.128
linux-image-4.15.0-129-generic-lpae (Ubuntu package) - update to 4.15.0-129.132~16.04.1
linux-image-4.15.0-129-lowlatency (Ubuntu package) - update to 4.15.0-129.132~16.04.1
linux-image-4.15.0-129-generic (Ubuntu package) - update to 4.15.0-129.132~16.04.1
linux-image-oracle (Ubuntu package) - addressed in versions 4.15.0.1062.51, 5.4.0.1034.31, 5.4.0.1034.36~18.04.18, 5.8.0.1021.20
linux-image-4.15.0-1062-oracle (Ubuntu package) - update to 4.15.0-1062.68~16.04.1
linux-image-oracle-lts-18.04 (Ubuntu package) - update to 4.15.0.1062.72
linux-image-gke-4.15 (Ubuntu package) - update to 4.15.0.1077.81
linux-image-gke (Ubuntu package) - addressed in versions 4.15.0.1077.81, 4.15.0.1091.92, 5.8.0.1023.23
linux-image-4.15.0-1077-gke (Ubuntu package) - update to 4.15.0-1077.82
linux-image-4.15.0-1077-raspi2 (Ubuntu package) - update to 4.15.0-1077.82
linux-image-4.15.0-1082-kvm (Ubuntu package) - update to 4.15.0-1082.84
linux-image-aws-hwe (Ubuntu package) - update to 4.15.0.1091.85
linux-image-gcp (Ubuntu package) - addressed in versions 4.15.0.1091.92, 5.4.0.1033.21, 5.4.0.1033.42, 5.8.0.1023.23
linux-image-aws-lts-18.04 (Ubuntu package) - update to 4.15.0.1091.93
linux-image-4.15.0-1091-aws (Ubuntu package) - update to 4.15.0-1091.96~16.04.1
linux-image-4.15.0-1091-gcp (Ubuntu package) - update to 4.15.0-1091.104~16.04.1
linux-image-gcp-lts-18.04 (Ubuntu package) - update to 4.15.0.1091.109
linux-image-4.15.0-1094-snapdragon (Ubuntu package) - update to 4.15.0-1094.103
linux-image-azure-lts-18.04 (Ubuntu package) - update to 4.15.0.1103.76
linux-image-azure (Ubuntu package) - addressed in versions 4.15.0.1103.78, 4.15.0.1103.96, 5.4.0.1035.17, 5.4.0.1035.33, 5.8.0.1023.23
linux-image-4.15.0-1103-azure (Ubuntu package) - addressed in versions 4.15.0-1103.114~14.04.1, 4.15.0-1103.114~16.04.1
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
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
python3-perf-debuginfo - update to 4.19.90-2011.6.0.0049
python2-perf - update to 4.19.90-2011.6.0.0049
python3-perf - update to 4.19.90-2011.6.0.0049
bpftool-debuginfo - 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-tools-libs - update to 4.19.91-26
python-perf - update to 4.19.91-26
perf - update to 4.19.91-26
kernel-tools-libs-devel - update to 4.19.91-26
kernel-tools - update to 4.19.91-26
kernel-headers - update to 4.19.91-26
kernel-devel - update to 4.19.91-26
kernel-debug-devel - update to 4.19.91-26
kernel-debug - update to 4.19.91-26
kernel - update to 4.19.91-26
bpftool - update to 4.19.91-26
linux-image-oem-osp1 (Ubuntu package) - addressed in versions 5.4.0.59.62, 5.4.0.59.65~18.04.54
linux-image-5.4.0-59-lowlatency (Ubuntu package) - addressed in versions 5.4.0-59.65, 5.4.0-59.65~18.04.1
linux-image-5.4.0-59-generic (Ubuntu package) - addressed in versions 5.4.0-59.65, 5.4.0-59.65~18.04.1
linux-image-5.4.0-59-generic-lpae (Ubuntu package) - addressed in versions 5.4.0-59.65, 5.4.0-59.65~18.04.1
linux-image-virtual-hwe-18.04 (Ubuntu package) - update to 5.4.0.59.65~18.04.54
linux-image-snapdragon-hwe-18.04 (Ubuntu package) - update to 5.4.0.59.65~18.04.54
linux-image-lowlatency-hwe-18.04 (Ubuntu package) - update to 5.4.0.59.65~18.04.54
linux-image-generic-lpae-hwe-18.04 (Ubuntu package) - update to 5.4.0.59.65~18.04.54
linux-image-generic-hwe-18.04 (Ubuntu package) - update to 5.4.0.59.65~18.04.54
linux-image-5.4.0-1026-raspi (Ubuntu package) - addressed in versions 5.4.0-1026.29, 5.4.0-1026.29~18.04.1
linux-image-raspi-hwe-18.04 (Ubuntu package) - update to 5.4.0.1026.30
linux-image-raspi (Ubuntu package) - addressed in versions 5.4.0.1026.61, 5.8.0.1016.19
linux-image-5.4.0-1031-kvm (Ubuntu package) - update to 5.4.0-1031.32
linux-image-5.4.0-1033-gcp (Ubuntu package) - addressed in versions 5.4.0-1033.35, 5.4.0-1033.35~18.04.1
linux-image-5.4.0-1033-gke (Ubuntu package) - update to 5.4.0-1033.35~18.04.1
linux-image-gke-5.4 (Ubuntu package) - update to 5.4.0.1033.35~18.04.2
linux-image-5.4.0-1034-aws (Ubuntu package) - addressed in versions 5.4.0-1034.35, 5.4.0-1034.35~18.04.1
linux-image-5.4.0-1034-oracle (Ubuntu package) - addressed in versions 5.4.0-1034.36, 5.4.0-1034.36~18.04.1
linux-image-5.4.0-1035-azure (Ubuntu package) - addressed in versions 5.4.0-1035.36, 5.4.0-1035.36~18.04.1
linux-image-oem-20.04 (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-generic (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-lowlatency (Ubuntu package) - update to 5.8.0-44.50~20.04.1
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-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-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-5.8.0-1019-kvm (Ubuntu package) - update to 5.8.0-1019.21
linux-image-5.8.0-1021-oracle (Ubuntu package) - update to 5.8.0-1021.22
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
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

• https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html
• https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=90bfdeef83f1d6c696039b6a917190dcbbad3220
• https://www.openwall.com/lists/oss-security/2020/10/30/1,
• http://www.openwall.com/lists/oss-security/2020/11/04/3
• https://bugzilla.redhat.com/show_bug.cgi?id=1893287,
• http://www.openwall.com/lists/oss-security/2020/10/30/1
• https://www.openwall.com/lists/oss-security/2020/11/04/3,
• https://security.netapp.com/advisory/ntap-20210702-0005/

• Privilege escalation in Linux kernel
• Ubuntu update for linux
• Ubuntu update for linux
• Ubuntu update for linux
• Ubuntu update for linux
• Amazon Linux AMI update for kernel
• Anolis OS update for kernel(ANCK)4.19
• openEuler 20.03 LTS update for kernel
• Fedora 32 update for kernel, kernel-headers, kernel-tools
• Fedora 33 update for kernel, kernel-headers, kernel-tools