CVE-2026-99151

drm/amd/display: Fix NULL sink dereference in USB4 bandwidth functions

Published Oct 28, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Fix NULL sink dereference in USB4 bandwidth functions

allocate_usb4_bandwidth_for_stream() and allocate_usb4_bandwidth() both
use ASSERT(stream->sink) before dereferencing stream->sink->link. ASSERT
is compiled out in production builds, so a NULL stream->sink causes a
NULL pointer dereference.

link_set_dpms_off() already guards two earlier accesses to stream->sink
with explicit NULL checks, confirming that stream->sink can legitimately
be NULL. The subsequent call to deallocate_usb4_bandwidth() had no
equivalent guard.

Replace the ASSERT() calls with proper NULL checks that return false
early, and add a matching stream->sink guard at the call site in
link_set_dpms_off() consistent with the surrounding pattern.

v2: Keep the existing ASSERT() calls for diagnostics (to report
unexpected NULL sink), and add explicit NULL checks that return false
before dereferencing stream->sink. Also add a matching stream->sink
guard at the deallocation call site in link_set_dpms_off(). (Alex)

(cherry picked from commit 98029a0ce61feb52c563f65349dd9b25f672e355)

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
First Time appeared Linux linux
Vendors & Products Linux linux
Type Values Removed Values Added
Weaknesses CWE-476
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix NULL sink dereference in USB4 bandwidth functions allocate_usb4_bandwidth_for_stream() and allocate_usb4_bandwidth() both use ASSERT(stream->sink) before dereferencing stream->sink->link. ASSERT is compiled out in production builds, so a NULL stream->sink causes a NULL pointer dereference. link_set_dpms_off() already guards two earlier accesses to stream->sink with explicit NULL checks, confirming that stream->sink can legitimately be NULL. The subsequent call to deallocate_usb4_bandwidth() had no equivalent guard. Replace the ASSERT() calls with proper NULL checks that return false early, and add a matching stream->sink guard at the call site in link_set_dpms_off() consistent with the surrounding pattern. v2: Keep the existing ASSERT() calls for diagnostics (to report unexpected NULL sink), and add explicit NULL checks that return false before dereferencing stream->sink. Also add a matching stream->sink guard at the deallocation call site in link_set_dpms_off(). (Alex) (cherry picked from commit 98029a0ce61feb52c563f65349dd9b25f672e355)
Title drm/amd/display: Fix NULL sink dereference in USB4 bandwidth functions
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 28, 2026, 10:35 AM
Reserved
Sep 25, 2026, 10:25 AM
Status
Received
Published
Oct 28, 2026, 11:17 AM
Modified
Oct 28, 2026, 11:17 AM
Severity
Moderate
Public date
Oct 28, 2026, 10:35 AM