Improper input validation in Linux kernel - CVE-2026-63851
Published: July 20, 2026
Vulnerability identifier: #VU138811
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-2026-63851
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 amdgpu vcn v4.0.5 encoder ring when processing command submission requests 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 v4.0.5 encoder functionality because 64-bit user fence writes are not supported.
How to mitigate CVE-2026-63851
Install security update from vendor's repository.