Out-of-bounds write in Linux kernel - CVE-2026-64366

Vulnerability identifier: #VU139601

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64366

CWE-ID: CWE-787

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service or execute arbitrary code.

The vulnerability exists due to an out-of-bounds write in wacom_wac_queue_insert in the Wacom HID driver when processing crafted input reports. A local user can send a specially crafted report to cause a denial of service or execute arbitrary code.

The issue is triggered when stale data in an empty kfifo is interpreted as a record length, corrupting the internal fifo state before a memcpy writes past a 256-byte buffer.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/57bdd10ad50d68341f500a7b330f0d8949e510ec
• https://git.kernel.org/stable/c/6b3014ec0e9a390ca563030b2d7689921f0daef5
• https://git.kernel.org/stable/c/ca899a926c11a59211b764b0155d9a1cdcc32b81

• Out-of-bounds write in Linux kernel hid driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0