EUVD-2026-66487
GHSA-g6j6-j6hv-j2v2
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Race condition requires precise kernel-scheduling timing to win reliably, warranting AC:H over the NVD's AC:L; PR:L reflects required local unprivileged account; AV:L is firm with no network vector.
Primary rating from Vendor (Linux).
CVSS VectorVendor: Linux
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
5DescriptionCVE.org
In the Linux kernel, the following vulnerability has been resolved:
Input: byd - synchronize timer deletion before freeing private data
byd_disconnect() uses timer_delete() before freeing the driver's private data. This does not wait for a running byd_clear_touch() callback, which dereferences the private data and its psmouse pointer. A callback racing with disconnect can therefore access the private data after it has been freed. The timer can also still be re-armed by byd_process_byte() while the disconnect is in progress.
Use timer_shutdown_sync() before freeing the private data: it waits for a running callback and turns any later re-arm attempt into a no-op.
AnalysisAI
Use-after-free race condition in the Linux kernel BYD PS/2 mouse driver allows a local low-privileged user to corrupt kernel memory by racing a device disconnect event against in-flight timer callbacks. Affected systems must run an unpatched Linux kernel with BYD PS/2 touchpad hardware present and the byd module loaded, spanning stable branches from approximately kernel 4.6 through pre-fix releases ahead of 6.18.46, 7.1.10, and 7.2. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires a local, low-privileged user account (PR:L per CVSS vector) on a host meeting all of the following conditions: BYD-branded PS/2 touchpad hardware must be physically present, the byd kernel module must be loaded and active, and the attacker must be capable of racing a device disconnect event against concurrent timer callback execution within the kernel scheduler's timing window. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 7.8 score (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) correctly identifies a local, low-privilege attack path with the high-impact triad characteristic of kernel memory corruption vulnerabilities. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A local user with a standard unprivileged account on a laptop equipped with a BYD PS/2 touchpad generates continuous rapid input through the BYD driver, keeping byd_process_byte() active and byd_clear_touch() timer callbacks firing repeatedly. The attacker simultaneously triggers a device disconnect event, racing the callback's dereference of the private data structure against byd_disconnect()'s deallocation of that same memory region. … |
| Remediation | Update to Linux stable release 6.18.46, 7.1.10, or 7.2 or later, which incorporate the fix commits available at https://git.kernel.org/stable/c/8dbfd8e32a13e116790780ed0be82b5a05eb9916, https://git.kernel.org/stable/c/2e509ef60ee41a2da0deb062c262bb530143fb37, and https://git.kernel.org/stable/c/c83e79c0842ed29860648bcce5022ef0ba5001c6. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, audit systems running Linux kernel versions 4.6 through 7.1 with BYD PS/2 touchpad hardware loaded (verify with lsmod | grep byd) to identify production deployments. …
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