Review reviewHigh

CVE-2026-63856

Linux

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/vcn: set no_user_fence for VCN v2.0 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 e2b5499fca55f1a32960a311bbb62e35891eaf73)

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: >= 1b61de45dfaff00b627e47349a019658e39268b9 < f264019be80de79f84f464846451445923bffea0, >= 1b61de45dfaff00b627e47349a019658e39268b9 < 5e777bc4cbe928ac0fd95e368fee1540f2ce4db2, >= 1b61de45dfaff00b627e47349a019658e39268b9 < ac06ce5cac9e711281585d09d00c6efcd9b86396, >= 1b61de45dfaff00b627e47349a019658e39268b9 < c71aecae98e42dcf2baf462df50b3a2cf1a93fe4, >= 1b61de45dfaff00b627e47349a019658e39268b9 < 8d80b293b41fcb5e9396db93e788b0f4ebcbafb7, >= 5.3
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