Out-of-bounds read in Linux kernel - CVE-2026-31697
Published: May 2, 2026
Vulnerability identifier: #VU128998
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-31697
CWE-ID: CWE-125
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 sensitive information.
The vulnerability exists due to an out-of-bounds read in sev_ioctl_do_get_id2 in the ccp/sev ioctl handler when handling a request to retrieve the CPU ID with a userspace buffer and length that are too small after a firmware command failure. A local user can issue a specially crafted ioctl request to disclose sensitive information.
The issue occurs when the firmware command fails due to an invalid length and the kernel still copies the firmware-required byte count to userspace.
How to mitigate CVE-2026-31697
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/06f06d88c05ce176c61fff8c72c372847b0dd2b5
- https://git.kernel.org/stable/c/09427bcb1715fb20a80b6acd5156dbf15ab5c363
- https://git.kernel.org/stable/c/1fbac0429a42adec830491757a2b53956dd797ea
- https://git.kernel.org/stable/c/2937f17bbeefb8e7608ff1f78cffbeb3d0281e5e
- https://git.kernel.org/stable/c/4f685dbfa87c546e51d9dc6cab379d20f275e114