high 7.1

CVE-2021-47097 json

Input: elantech - fix stack out of bound access in elantech_change_report_id()

published 2024-03-04 2 y ago modified 2026-06-17 4 mo ago also EUVD-2021-33745

cvss: 7.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits: 0; none known

In the Linux kernel, the following vulnerability has been resolved:

The array param[] in elantech_change_report_id() must be at least 3 bytes, because elantech_read_reg_params() is calling ps2_command() with PSMOUSE_CMD_GETINFO, that is going to access 3 bytes from param[], but it's defined in the stack as an array of 2 bytes, therefore we have a potential stack out-of-bounds access here, also confirmed by KASAN:

[ 6.512374] BUG: KASAN: stack-out-of-bounds in __ps2_command+0x372/0x7e0 [ 6.512397] Read of size 1 at addr ffff8881024d77c2 by task kworker/2:1/118

[ 6.512416] CPU: 2 PID: 118 Comm: kworker/2:1 Not tainted 5.13.0-22-generic #22+arighi20211110 [ 6.512428] Hardware name: LENOVO 20T8000QGE/20T8000QGE, BIOS R1AET32W (1.08 ) 08/14/2020 [ 6.512436] Workqueue: events_long serio_handle_event [ 6.512453] Call Trace: [ 6.512462] show_stack+0x52/0x58 [ 6.512474] dump_stack+0xa1/0xd3 [ 6.512487] print_address_description.constprop.0+0x1d/0x140 [ 6.512502] ? __ps2_command+0x372/0x7e0 [ 6.512516] __kasan_report.cold+0x7d/0x112 [ 6.512527] ? _raw_write_lock_irq+0x20/0xd0 [ 6.512539] ? __ps2_command+0x372/0x7e0 [ 6.512552] kasan_report+0x3c/0x50 [ 6.512564] __asan_load1+0x6a/0x70 [ 6.512575] __ps2_command+0x372/0x7e0 [ 6.512589] ? ps2_drain+0x240/0x240 [ 6.512601] ? dev_printk_emit+0xa2/0xd3 [ 6.512612] ? dev_vprintk_emit+0xc5/0xc5 [ 6.512621] ? __kasan_check_write+0x14/0x20 [ 6.512634] ? mutex_lock+0x8f/0xe0 [ 6.512643] ? __mutex_lock_slowpath+0x20/0x20 [ 6.512655] ps2_command+0x52/0x90 [ 6.512670] elantech_ps2_command+0x4f/0xc0 [psmouse] [ 6.512734] elantech_change_report_id+0x1e6/0x256 [psmouse] [ 6.512799] ? elantech_report_trackpoint.constprop.0.cold+0xd/0xd [psmouse] [ 6.512863] ? ps2_command+0x7f/0x90 [ 6.512877] elantech_query_info.cold+0x6bd/0x9ed [psmouse] [ 6.512943] ? elantech_setup_ps2+0x460/0x460 [psmouse] [ 6.513005] ? psmouse_reset+0x69/0xb0 [psmouse] [ 6.513064] ? psmouse_attr_set_helper+0x2a0/0x2a0 [psmouse] [ 6.513122] ? phys_pmd_init+0x30e/0x521 [ 6.513137] elantech_init+0x8a/0x200 [psmouse] [ 6.513200] ? elantech_init_ps2+0xf0/0xf0 [psmouse] [ 6.513249] ? elantech_query_info+0x440/0x440 [psmouse] [ 6.513296] ? synaptics_send_cmd+0x60/0x60 [psmouse] [ 6.513342] ? elantech_query_info+0x440/0x440 [psmouse] [ 6.513388] ? psmouse_try_protocol+0x11e/0x170 [psmouse] [ 6.513432] psmouse_extensions+0x65d/0x6e0 [psmouse] [ 6.513476] ? psmouse_try_protocol+0x170/0x170 [psmouse] [ 6.513519] ? mutex_unlock+0x22/0x40 [ 6.513526] ? ps2_command+0x7f/0x90 [ 6.513536] ? psmouse_probe+0xa3/0xf0 [psmouse] [ 6.513580] psmouse_switch_protocol+0x27d/0x2e0 [psmouse] [ 6.513624] psmouse_connect+0x272/0x530 [psmouse] [ 6.513669] serio_driver_probe+0x55/0x70 [ 6.513679] really_probe+0x190/0x720 [ 6.513689] driver_probe_device+0x160/0x1f0 [ 6.513697] device_driver_attach+0x119/0x130 [ 6.513705] ? device_driver_attach+0x130/0x130 [ 6.513713] __driver_attach+0xe7/0x1a0 [ 6.513720] ? device_driver_attach+0x130/0x130 [ 6.513728] bus_for_each_dev+0xfb/0x150 [ 6.513738] ? subsys_dev_iter_exit+0x10/0x10 [ 6.513748] ? _raw_write_unlock_bh+0x30/0x30 [ 6.513757] driver_attach+0x2d/0x40 [ 6.513764] serio_handle_event+0x199/0x3d0 [ 6.513775] process_one_work+0x471/0x740 [ 6.513785] worker_thread+0x2d2/0x790 [ 6.513794] ? process_one_work+0x740/0x740 [ 6.513802] kthread+0x1b4/0x1e0 [ 6.513809] ? set_kthread_struct+0x80/0x80 [ 6.513816] ret_from_fork+0x22/0x30

[ 6.513832] The buggy address belongs to the page: [ 6.513838] page:00000000bc35e189 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1024d7 [ 6.513847] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff) [ 6.513860] raw: 0 ---truncated---

Patch / fix

fixed in 1 distros 6 links 4

Linux Linux 5.4.169, 5.10.89, 5.15.12, 5.16

debian ubuntu red hat suse almalinux rocky linux

linux Debian 14, Debian 13, Debian 12 5.15.15-1

debian advisories DEBIAN-CVE-2021-47097

linux Ubuntu 20.04 LTS 5.4.0-105.119
linux-aws Ubuntu 20.04 LTS 5.4.0-1069.73
linux-gcp Ubuntu 20.04 LTS 5.4.0-1068.72
linux-ibm Ubuntu 20.04 LTS 5.4.0-1018.20
linux-kvm Ubuntu 20.04 LTS 5.4.0-1059.62
linux-azure Ubuntu 20.04 LTS 5.4.0-1073.76
linux-gkeop Ubuntu 20.04 LTS 5.4.0-1037.38
linux-raspi Ubuntu 20.04 LTS 5.4.0-1056.63

ubuntu advisories UBUNTU-CVE-2021-47097

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel RHEL 8 4.18.0-553.22.1.el8_10
perf RHEL 8 4.18.0-553.22.1.el8_10
bpftool RHEL 8 4.18.0-553.22.1.el8_10
kernel-core RHEL 8 4.18.0-553.22.1.el8_10
kernel-tools RHEL 8 4.18.0-553.22.1.el8_10
python3-perf RHEL 8 4.18.0-553.22.1.el8_10
kernel-modules RHEL 8 4.18.0-553.22.1.el8_10
kernel-zfcpdump RHEL 8 4.18.0-553.22.1.el8_10

red hat advisories RHSA-2024:7000 RHSA-2024:7001

kernel-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
kernel-syms-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
kernel-source-azure SLE Module for Public Cloud 15 SP5, openSUSE Leap 15.5 5.14.21-150500.33.48.1
kernel-64kb SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS, Enterprise Storage 7.1 5.3.18-150300.59.158.1
kernel-syms SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +1 more 5.3.18-150300.59.158.1
kernel-source SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +1 more 5.3.18-150300.59.158.1
kernel-default SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Micro 5.2 +5 more 5.3.18-150300.59.158.1
kernel-preempt SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +1 more 5.3.18-150300.59.158.1

suse advisories SUSE-SU-2024:1490-1 SUSE-SU-2024:1489-1 SUSE-SU-2024:1480-1 SUSE-SU-2024:1466-1 SUSE-SU-2024:1465-1 SUSE-SU-2024:1321-1

kernel AlmaLinux 8 4.18.0-553.22.1.el8_10
perf AlmaLinux 8 4.18.0-553.22.1.el8_10
bpftool AlmaLinux 8 4.18.0-553.22.1.el8_10
kernel-core AlmaLinux 8 4.18.0-553.22.1.el8_10
kernel-tools AlmaLinux 8 4.18.0-553.22.1.el8_10
python3-perf AlmaLinux 8 4.18.0-553.22.1.el8_10
kernel-modules AlmaLinux 8 4.18.0-553.22.1.el8_10
kernel-zfcpdump AlmaLinux 8 4.18.0-553.22.1.el8_10

almalinux advisories ALSA-2024:7000 ALSA-2024:7001

kernel Rocky Linux 8 4.18.0-553.22.1.el8_10
kernel-rt Rocky Linux 8 4.18.0-553.22.1.rt7.363.el8_10

rocky linux advisories RLSA-2024:7000 RLSA-2024:7001

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-47097 updated 2026-11-07 cvss 6.0

kernel: Input: elantech - fix stack out of bound access in elantech_change_report_id()

Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
affected: no fix available
Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.22.1.el8_10, kernel 4.18.0-553.22.1.el8_10, bpftool 4.18.0-553.22.1.el8_10, kernel-core 4.18.0-553.22.1.el8_10, kernel-tools 4.18.0-553.22.1.el8_10, python3-perf 4.18.0-553.22.1.el8_10, +15 more Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.22.1.el8_10
fixed: vendor fix RHSA-2024:7000
Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, +4 more Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules-extra 4.18.0-553.22.1.rt7.363.el8_10, +2 more
fixed: vendor fix RHSA-2024:7001
Red Hat OpenShift AI 8 rhoai/odh-rhel8-operator v2.13.1-2, rhoai/odh-dashboard-rhel8 v2.13.1-1, rhoai/odh-modelmesh-rhel8 v2.13.1-1, rhoai/odh-operator-bundle v2.13.1-2, rhoai/odh-rhel8-operator v2.14.0-24, rhoai/odh-dashboard-rhel8 v2.14.0-11, +56 more
fixed: vendor fix RHBA-2024:8413

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-03-06)

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

git.kernel.org https://git.kernel.org/stable/c/a7f95328c6f0afffdc4555f16e3bbab8bbf0d9be referenced PoC, tagged "exploit" by a source, unverified
git.kernel.org https://git.kernel.org/stable/c/676c572439e58b7ee6b7ca3f1e5595382921045c referenced PoC, tagged "exploit" by a source, unverified
git.kernel.org https://git.kernel.org/stable/c/dfd5b60b5342b6b505a104e48f08ad9b9bdbbd7b referenced PoC, tagged "exploit" by a source, unverified
git.kernel.org https://git.kernel.org/stable/c/1d72d9f960ccf1052a0630a68c3d358791dbdaaa referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.1	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products

Linux Linux

Classification

Weakness

CWE-125 Out-of-bounds Read

Technology feeds

Linux kernel rss critical rss

References

git.kernel.org /stable/c/a7f95328c6f0afffdc4555f16e3bbab8bbf0d9be
exploit, mailing-list, patch
git.kernel.org /stable/c/676c572439e58b7ee6b7ca3f1e5595382921045c
exploit, mailing-list, patch
git.kernel.org /stable/c/dfd5b60b5342b6b505a104e48f08ad9b9bdbbd7b
exploit, mailing-list, patch
git.kernel.org /stable/c/1d72d9f960ccf1052a0630a68c3d358791dbdaaa
exploit, mailing-list, patch

Sources

CVE List CVE-2021-47097
NVD CVE-2021-47097

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary