Linux Kernel up to 7.2.12 USB4 Bandwidth Management allocate_usb4_bandwidth_for_stream null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.12 and classified as critical. Impacted is the function allocate_usb4_bandwidth_for_stream of the component USB4 Bandwidth Management. The manipulation results in null pointer dereference. This vulnerability is reported as CVE-2026-99151. The attack requires a local approach. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 7.2.12. Affected is the function allocate_usb4_bandwidth_for_stream of the component USB4 Bandwidth Management. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

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)

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-99151 since 09/25/2026. The exploitability is told to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available.

Upgrading to version 7.2.13 eliminates this vulnerability. Applying the patch 4c8b5e5b9776ad08138d79b14238c5742b32911b/55a67aa89342545b89f469dea6f29bfb6fac6f3d is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5
• 7.2.6
• 7.2.7
• 7.2.8
• 7.2.9
• 7.2.10
• 7.2.11
• 7.2.12

License

• open-source

Website

• Vendor: https://www.kernel.org/

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