CVE-2026-98859
Description
A flaw was found in the Linux kernel's Human Interface Device (HID) multitouch driver. When a multitouch device is disconnected or removed, the driver fails to prevent the release timer from being rescheduled by incoming input reports. Once the driver deallocates the device data, the timer callback executes and attempts to access the freed memory, resulting in a use-after-free condition. A local attacker could exploit this flaw to cause a Denial of Service (DoS) by crashing the system.
Statement
A race in the HID multitouch removal path can rearm release_timer after timer_delete_sync has already returned. The mt_device object is freed after mt_remove completes, but the queued timer can later execute mt_expired_timeout and dereference the released td object. The callback reads td hdev and performs a bit operation on td mt_io_flags, so the issue includes access to and modification of freed memory rather than only a harmless stale timer warning. For the CVSS the PR:N value reflects a malicious attached HID device that can deliver reports and disconnect without holding an account or privilege on the target. The paranoid AV:A interpretation is applicable only where an affected HID transport can be reached over an adjacent connection such as Bluetooth. Typical USB exploitation instead requires physical device access and the race has AC:H because a report must arrive during the narrow teardown window. The issue is not directly reachable over ordinary IP networks or the public Internet.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | N/A |
| Attack Vector | Adjacent Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
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