Improper input validation in Linux kernel - CVE-2026-63853
Published: July 20, 2026
Vulnerability identifier: #VU138794
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-63853
CWE-ID: CWE-20
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 cause a denial of service.
The vulnerability exists due to improper input validation in the VCN v4.0 encoder ring submission handling when processing command submissions with user fences. A local user can submit a crafted command stream with a user fence to cause a denial of service.
The issue affects VCN v4.0 encoder functionality, and stems from unsupported 64-bit user fence writes being accepted.
How to mitigate CVE-2026-63853
Install security update from vendor's repository.