Review reviewHigh

CVE-2026-63855

Linux

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/vcn: set no_user_fence for VCN v2.5 enc/dec rings VCN encoder and decoder rings do not support 64-bit user fence writes, reject CS submissions with user fences. (cherry picked from commit efc9dd5590894109bce9a0bfe1fa5592dd6b20b1)

CVSS: 7.8
EPSS: -
CISA KEV: Not listed
Published: 2026.07.20

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability-

Technical severityCVSS 7.8

Vulnerability overview

Affected product and versions

Product: Linux
Affected versions: >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 2c6fb056567efb49f8674108b86088a1cfaa86d0, >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 8f0ea4524dc71c6c9ec97f2711f46e12f624140f, >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 602d4c5872b25ddd4d82fb2025efb9a05b187bb3, >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 5a3c6f76cab164a5d803084908d7050f649ab7f9, >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 4f317863a3ab212a027d8c8c3cc3af4e3fb95704, >= 5.4
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Linux and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE: Not available