CVE-2026-63852
Description
A flaw was found in the Linux kernel's AMD GPU (Graphics Processing Unit) Video Core Next (VCN) component. This vulnerability arises because the VCN encoder and decoder rings do not properly handle 64-bit user fence writes, leading to the rejection of command submissions that utilize these fences. An attacker could potentially exploit this to cause a denial of service by preventing legitimate operations that rely on 64-bit user fence writes.
Statement
This vulnerability is rated Moderate because exploitation requires local access and is constrained to systems utilizing specific AMD GPU hardware containing the Video Core Next (VCN) v4.0.3 block. On standard Red Hat Enterprise Linux installations where unprivileged users lack direct rendering manager device permissions or where affected AMD GPUs are not deployed, exposure is minimal. An attacker with local access could trigger a denial of service by causing command submission failures on the encoder ring, but the issue does not allow privilege escalation or unauthorized data access.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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