Use of Uninitialized Variable in Linux kernel - CVE-2026-63966
Published: July 20, 2026
Vulnerability identifier: #VU138686
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-63966
CWE-ID: CWE-457
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to disclose uninitialized kernel stack memory to userspace.
The vulnerability exists due to an uninitialized stack variable in adis16550_trigger_handler() when handling triggered buffer data collection. A local user can trigger the handler and read leaked stack bytes from the resulting userspace buffer to disclose uninitialized kernel stack memory to userspace.
Bytes 28 through 31 of the scan data buffer remain uninitialized and are exposed on each trigger due to timestamp alignment.
How to mitigate CVE-2026-63966
Install security update from vendor's repository.