CVE-2026-64364 - Vulnerability Details

- HID: multitouch: fix out-of-bounds bit access on mt_io_flags

Description

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

HID: multitouch: fix out-of-bounds bit access on mt_io_flags

mt_io_flags is a single unsigned long, but mt_process_slot(),
mt_release_pending_palms() and mt_release_contacts() use it as a
per-slot bitmap indexed by the slot number. That slot number is only
bounded by td->maxcontacts, which is taken from the device's
ContactCountMaximum feature report and can be up to 255, not by
BITS_PER_LONG.

As a result, a multitouch device that advertises a large contact count
makes set_bit()/clear_bit() operate past the mt_io_flags word and
corrupt the adjacent members of struct mt_device. The sticky-fingers
release timer is the easiest way to reach this. mt_release_contacts()
runs

for (i = 0; i < mt->num_slots; i++)
clear_bit(i, &td->mt_io_flags);

with num_slots == maxcontacts. For maxcontacts around 250 the loop
clears the bits that overlap td->applications.next, zeroing that list
head, and the list_for_each_entry() that immediately follows then
dereferences NULL. The kernel panics from timer (softirq) context. On a
KASAN build this shows up as a general protection fault in
mt_release_contacts() with a null-ptr-deref at offset 0x58, which is
offsetof(struct mt_application, num_received).

The state is reachable from an untrusted USB or Bluetooth HID
multitouch device; no local privileges are required.

Store the per-slot active state in a separately allocated bitmap sized
for maxcontacts, the same pattern already used for pending_palm_slots,
and keep only MT_IO_FLAGS_RUNNING in mt_io_flags. The two
"mt_io_flags & MT_IO_SLOTS_MASK" arming checks become
bitmap_empty(td->active_slots, td->maxcontacts).

Move MT_IO_FLAGS_RUNNING back to bit 0. It was bumped to bit 32 by the
same commit to leave the low byte for the slot bits; with the slot bits
gone it fits in bit 0 again, which also keeps it within the unsigned
long on 32-bit.

Published: 2026-07-25

Score: 8.8 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

In the Linux kernel’s multitouch subsystem a single unsigned long variable, mt_io_flags, is mistakenly treated as a per‑slot bitmap. When a device reports up to 255 contacts, code paths such as mt_release_contacts() write bits beyond the allocated word, corrupting adjacent structure fields, which triggers a null pointer dereference during a timer context and forces a kernel panic. The flaw is exploitable by any untrusted USB or Bluetooth HID multitouch device and requires no local privileges.

Affected Systems

All Linux kernel builds that lack the patch committed to fix the out‑of‑bounds bit access are vulnerable. The flaw resides in the multitouch driver, so any system using a kernel that supports multitouch over USB or Bluetooth and has not applied the recent update is affected.

Risk and Exploitability

The CVSS score of 8.8 indicates high severity, yet the EPSS score of less than 1% shows a very low current probability of exploitation and the vulnerability is not listed in the CISA KEV catalog. An attacker can trigger the bug simply by connecting a multitouch device advertising a large contact count; no privilege escalation is required. The primary impact is a kernel panic, effectively causing denial of service until the system is rebooted. The overall risk is therefore high severity but low likelihood under current conditions.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`fc488f675344931ffab6a51c43691065ec006567`	affected	< 12e90656e330ff8bbaf2f29c535fdb8a11cc6f55
`77711d850bed75ae7142c3d1f22c1a8b4d049c33`	affected	< 152983d87387f6a8ae72b73474cfa55fbcf1ec75
`6acfe25968913788d30ec0eedd80178c4ea3f1d0`	affected	< b5c037d6b807017e74a115288f81bc9cd5a5aab8
`d280c138e66be87d1fccfed42593f02fdb893905`	affected	< a6d5ce2e1a2d7bf189bde8a659d04b65f0b0725d
`f32fea4c0234c971c12e46d76612cdc2dd4bb046`	affected	< e24918ee67c4dc3d20d4670750e46e9b160365f4
`46f781e0d151844589dc2125c8cce3300546f92a`	affected	< 37daa8c96bd563d03150e23f094cb60703594a6d
`46f781e0d151844589dc2125c8cce3300546f92a`	affected	< 6493ebf9489efef0105078377b973ab33d51af22
`46f781e0d151844589dc2125c8cce3300546f92a`	affected	< 8813b0612275cc61fe9e6603d0ee019247ade6be
`59bd04163e6451b9c7275277882ed9f4abfa2051`	affected	—
`5.10.246`	affected	< 5.10.261
`5.15.196`	affected	< 5.15.212
`6.1.158`	affected	< 6.1.178
`6.6.114`	affected	< 6.6.145
`6.12.55`	affected	< 6.12.97
`6.17.5`	affected	< 6.18

Linux

affected

Version	Status	Constraints
`6.18`	affected	—
`0`	unaffected	< 6.18
`5.10.261`	unaffected	≤ 5.10.*
`5.15.212`	unaffected	≤ 5.15.*
`6.1.178`	unaffected	≤ 6.1.*
`6.6.145`	unaffected	≤ 6.6.*
`6.12.97`	unaffected	≤ 6.12.*
`6.18.39`	unaffected	≤ 6.18.*
`7.1.4`	unaffected	≤ 7.1.*
`7.2-rc3`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[fc488f675344931ffab6a51c43691065ec006567,12e90656e330ff8bbaf2f29c535fdb8a11cc6f55)`	affected	code_commit	—
`[77711d850bed75ae7142c3d1f22c1a8b4d049c33,152983d87387f6a8ae72b73474cfa55fbcf1ec75)`	affected	code_commit	—
`[6acfe25968913788d30ec0eedd80178c4ea3f1d0,b5c037d6b807017e74a115288f81bc9cd5a5aab8)`	affected	code_commit	—
`[d280c138e66be87d1fccfed42593f02fdb893905,a6d5ce2e1a2d7bf189bde8a659d04b65f0b0725d)`	affected	code_commit	—
`[f32fea4c0234c971c12e46d76612cdc2dd4bb046,e24918ee67c4dc3d20d4670750e46e9b160365f4)`	affected	code_commit	—
`[46f781e0d151844589dc2125c8cce3300546f92a,37daa8c96bd563d03150e23f094cb60703594a6d)`	affected	code_commit	—
`[46f781e0d151844589dc2125c8cce3300546f92a,6493ebf9489efef0105078377b973ab33d51af22)`	affected	code_commit	—
`[46f781e0d151844589dc2125c8cce3300546f92a,8813b0612275cc61fe9e6603d0ee019247ade6be)`	affected	code_commit	—
`[59bd04163e6451b9c7275277882ed9f4abfa2051,59bd04163e6451b9c7275277882ed9f4abfa2051]`	affected	code_commit	—
`[5.10.246,5.10.261)`	affected	semver	—
`[5.15.196,5.15.212)`	affected	semver	—
`[6.1.158,6.1.178)`	affected	semver	—
`[6.6.114,6.6.145)`	affected	semver	—
`[6.12.55,6.12.97)`	affected	semver	—
`[6.17.5,6.18)`	affected	semver	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[6.18,6.18]`	affected	semver	—
`[0,6.18)`	unaffected	semver	—
`[5.10.261,5.11.0)`	unaffected	semver	—
`[5.15.212,5.16.0)`	unaffected	semver	—
`[6.1.178,6.2.0)`	unaffected	semver	—
`[6.6.145,6.7.0)`	unaffected	semver	—
`[6.12.97,6.13.0)`	unaffected	semver	—
`[6.18.39,6.19.0)`	unaffected	semver	—
`[7.1.4,7.2.0)`	unaffected	semver	—
`[7.2-rc3,*]`	unaffected	generic	—

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Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Upgrade to a kernel version that includes the HID multitouch patch commit, such as the latest stable release provided by your distribution.
If an immediate kernel upgrade is not feasible, disable or restrict the multitouch driver for untrusted devices by unloading the module or applying udev rules that block HID multitouch devices reporting a contact count exceeding a safe threshold.
Continuously monitor system logs for OOPS and panic messages related to the multitouch subsystem, and schedule an immediate reboot when such an event occurs to restore normal operation.

Generated by OpenCVE AI on August 5, 2026 at 00:58 UTC.

Tracking

Sign in to view the affected projects.

Advisories

Source	ID	Title
Debian DLA	DLA-4717-1	linux security update
Debian DLA	DLA-4720-1	linux security update
Debian DLA	DLA-4723-1	linux-6.1 security update
Debian DLA	DLA-4724-1	linux-6.12 new package
Debian DSA	DSA-6405-1	linux security update

No CVSS v4.0

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00345.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/12e90656e330ff8bbaf2f29c535fdb8a11cc6f55
https://git.kernel.org/stable/c/152983d87387f6a8ae72b73474cfa55fbcf1ec75
https://git.kernel.org/stable/c/37daa8c96bd563d03150e23f094cb60703594a6d
https://git.kernel.org/stable/c/6493ebf9489efef0105078377b973ab33d51af22
https://git.kernel.org/stable/c/8813b0612275cc61fe9e6603d0ee019247ade6be
https://git.kernel.org/stable/c/a6d5ce2e1a2d7bf189bde8a659d04b65f0b0725d
https://git.kernel.org/stable/c/b5c037d6b807017e74a115288f81bc9cd5a5aab8
https://git.kernel.org/stable/c/e24918ee67c4dc3d20d4670750e46e9b160365f4
https://lore.kernel.org/linux-cve-announce/2026072521-CVE-2026-64364-7c96@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-64364
https://www.cve.org/CVERecord?id=CVE-2026-64364

History

Tue, 04 Aug 2026 15:00:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-119

Wed, 29 Jul 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-476
References		https://lore.kernel.org/linux-cve-announce/2026072521-CVE-2026-64364-7c96@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-64364 https://www.cve.org/CVERecord?id=CVE-2026-64364
Metrics	threat_severity `None`	threat_severity `Important`

Tue, 28 Jul 2026 16:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-119

Mon, 27 Jul 2026 05:15:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 8.8, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}`

Sat, 25 Jul 2026 09:30:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: HID: multitouch: fix out-of-bounds bit access on mt_io_flags mt_io_flags is a single unsigned long, but mt_process_slot(), mt_release_pending_palms() and mt_release_contacts() use it as a per-slot bitmap indexed by the slot number. That slot number is only bounded by td->maxcontacts, which is taken from the device's ContactCountMaximum feature report and can be up to 255, not by BITS_PER_LONG. As a result, a multitouch device that advertises a large contact count makes set_bit()/clear_bit() operate past the mt_io_flags word and corrupt the adjacent members of struct mt_device. The sticky-fingers release timer is the easiest way to reach this. mt_release_contacts() runs for (i = 0; i < mt->num_slots; i++) clear_bit(i, &td->mt_io_flags); with num_slots == maxcontacts. For maxcontacts around 250 the loop clears the bits that overlap td->applications.next, zeroing that list head, and the list_for_each_entry() that immediately follows then dereferences NULL. The kernel panics from timer (softirq) context. On a KASAN build this shows up as a general protection fault in mt_release_contacts() with a null-ptr-deref at offset 0x58, which is offsetof(struct mt_application, num_received). The state is reachable from an untrusted USB or Bluetooth HID multitouch device; no local privileges are required. Store the per-slot active state in a separately allocated bitmap sized for maxcontacts, the same pattern already used for pending_palm_slots, and keep only MT_IO_FLAGS_RUNNING in mt_io_flags. The two "mt_io_flags & MT_IO_SLOTS_MASK" arming checks become bitmap_empty(td->active_slots, td->maxcontacts). Move MT_IO_FLAGS_RUNNING back to bit 0. It was bumped to bit 32 by the same commit to leave the low byte for the slot bits; with the slot bits gone it fits in bit 0 again, which also keeps it within the unsigned long on 32-bit.
Title		HID: multitouch: fix out-of-bounds bit access on mt_io_flags
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/12e90656e330ff8bbaf2f29c535fdb8a11cc6f55 https://git.kernel.org/stable/c/152983d87387f6a8ae72b73474cfa55fbcf1ec75 https://git.kernel.org/stable/c/37daa8c96bd563d03150e23f094cb60703594a6d https://git.kernel.org/stable/c/6493ebf9489efef0105078377b973ab33d51af22 https://git.kernel.org/stable/c/8813b0612275cc61fe9e6603d0ee019247ade6be https://git.kernel.org/stable/c/a6d5ce2e1a2d7bf189bde8a659d04b65f0b0725d https://git.kernel.org/stable/c/b5c037d6b807017e74a115288f81bc9cd5a5aab8 https://git.kernel.org/stable/c/e24918ee67c4dc3d20d4670750e46e9b160365f4

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-07-25T08:50:19.441Z

Updated: 2026-08-05T12:41:06.503Z

Reserved: 2026-07-19T15:36:31.783Z

Link: CVE-2026-64364

Vulnrichment

No data.

NVD

Status : Awaiting Analysis

Published: 2026-07-25T10:17:19.110

Modified: 2026-08-11T15:01:50.637

Link: CVE-2026-64364

Redhat

Severity : Important

Publid Date: 2026-07-25T00:00:00Z

Links: CVE-2026-64364 - Bugzilla

OpenCVE Enrichment

Updated: 2026-08-05T01:00:07Z

Weaknesses

CWE-476
NULL Pointer Dereference

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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