CVE-2026-64366
Received Received - Intake

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Vulnerability report for CVE-2026-64366, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-07-25

Last updated on: 2026-07-25

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: HID: wacom: fix slab-out-of-bounds write in wacom_wac_queue_insert wacom_wac_queue_insert() calls kfifo_skip() in a loop when the kfifo doesn't have enough space for the incoming report. If the kfifo is empty, kfifo_skip() reads stale data left in the kmalloc'd buffer via __kfifo_peek_n() and interprets it as a record length, advancing fifo->out by that garbage value. This corrupts the internal kfifo state, causing kfifo_unused() to return a value much larger than the actual buffer size, which bypasses __kfifo_in_r()'s guard: if (len + recsize > kfifo_unused(fifo)) return 0; kfifo_copy_in() then performs an out-of-bounds memcpy, writing up to 3842 bytes past the 256-byte buffer. Add a !kfifo_is_empty() condition to the while loop so kfifo_skip() is never called on an empty fifo, and check the return value of kfifo_in() to reject reports that are too large for the fifo.

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Meta Information

Published
2026-07-25
Last Modified
2026-07-25
Generated
2026-07-25
AI Q&A
2026-07-25
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wacom wacom *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a slab-out-of-bounds write in the Linux kernel's HID wacom driver. It occurs in the wacom_wac_queue_insert function when processing input reports. The issue arises when a kfifo buffer lacks space, causing kfifo_skip to read stale data from an empty buffer. This corrupts the kfifo state, leading to an incorrect buffer size calculation and an out-of-bounds memory write of up to 3842 bytes past a 256-byte buffer.

Detection Guidance

This vulnerability is specific to the Linux kernel's HID wacom driver and requires kernel-level inspection. Detection involves checking kernel logs for slab-out-of-bounds errors or examining the wacom driver code for the described flaw. Commands like dmesg | grep -i wacom or journalctl -k | grep -i wacom may help identify related errors.

Impact Analysis

This vulnerability could allow an attacker with local access to execute arbitrary code or cause a denial of service by triggering a buffer overflow. It may lead to system crashes, data corruption, or privilege escalation on affected Linux systems using Wacom devices.

Mitigation Strategies

Apply the latest kernel update or patch that resolves this issue. If a patch is unavailable, consider disabling the wacom driver temporarily or restricting access to HID devices until a fix is applied.

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