amdgpu display code used by Linux systems when HDCP-protected displays are managed through certain USB-C dock and DisplayPort Multi-Stream Transport configurations; it does not call for a Windows Update, an AMD Software: Adrenalin Edition update, or a firmware update on a Windows PC.The immediate action is for administrators with AMD-powered Linux endpoints, dual-boot systems, Linux workstations, virtual-machine hosts, or appliance images: verify that the distribution kernel package includes the vendor’s backport, then reboot into that kernel. The upstream Linux CVE team says the fault was introduced in Linux 5.5 and has fixes in 6.1.138, 6.6.90, 6.12.28, 6.14.6, and 6.15-rc5. That list is useful, but it is not a complete patch-status guide for enterprise distributions, which routinely carry fixes in much older-looking kernel version strings.
The submitted NVD page’s August 11, 2026 timestamp should also be treated with care. The underlying patch was posted to the AMD graphics mailing list on April 17, 2025, entered stable-kernel queues in May 2025, and the Linux kernel CVE team announced CVE-2025-37903 on May 20, 2025. In other words, a 2026 NVD publication or refresh is a database event, not evidence of a newly discovered AMD graphics defect or a newly released fix.
A USB-C dock unplug can leave HDCP holding a dead connector
The Linux kernel CVE team’s advisory describes a slab use-after-free in
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c. HDCP, or High-bandwidth Digital Content Protection, is the display-content protection layer commonly encountered when protected video travels over HDMI, DisplayPort, or USB-C docking hardware.
The vulnerable code retained copies of
amdgpu_dm_connectorpointers without first increasing their
krefreference counts. That is a lifetime-management error: Linux could destroy the connector object when a dock was unplugged while the HDCP subsystem still retained a pointer to it. On reconnect, HDCP could dereference that stale pointer.
The practical reproduction described in the upstream report is unusually concrete: use an AMD Linux system with a USB-C dock, unplug it, and plug it back in. Kernel AddressSanitizer then caught a use-after-free read in the AMD GPU driver’s display-property validation work. The report’s allocation trace points to DisplayPort MST connector creation, while the freeing trace points to destruction of that connector during the display topology change.
This is why the advisory should not be read as a blanket “AMD GPU vulnerability.” The affected path combines several conditions: Linux, the open-source AMDGPU display stack, HDCP activity, a removable display connection, and the relevant connector lifecycle. A desktop Radeon card driving a directly attached monitor may never exercise it. A dock-heavy laptop fleet is more relevant than a static workstation fleet.
The patch itself is modest but specific. As posted to the AMD graphics list by Mario Limonciello, it acquires a connector reference before storing the pointer and releases the prior reference when replacing it. That directly addresses the bug rather than disabling HDCP or working around dock hot-plug events.
The CVSS numbers tell two different stories
Ubuntu currently labels CVE-2025-37903 as a Medium-priority issue while displaying a CVSS 3.1 score of 7.8, rated High. Its newer CVSS 4.0 score is 5.4, rated Medium, with a physical attack vector and high attack complexity.
Those scores can look contradictory, but the underlying assessment is more informative than the headline number. The older CVSS 3.1 vector treats the issue as a low-complexity local attack requiring low privileges and assigns high confidentiality, integrity, and availability impact. The CVSS 4.0 assessment more explicitly reflects the demonstrated trigger: access to the physical docking/display path and a complicated hardware-state transition.
Neither score proves practical code execution. A use-after-free in kernel code deserves serious treatment because stale object references can produce crashes, memory corruption, and potentially security consequences depending on allocator behavior and a workable exploitation primitive. But the upstream advisory is a bug-fix notice, not an exploit write-up; it documents a KASAN-detected invalid read during dock reconnection. The records reviewed for this report do not describe public exploitation of this CVE.
For patch prioritization, the risk is best described as locally reachable kernel memory corruption in a narrow but realistic hardware workflow. It is not a remotely reachable HDCP flaw that an internet-facing service exposes, and it is not evidence that a protected movie stream can compromise a system by itself.
Upstream version numbers are not enough for distro fleets
The Linux kernel CVE announcement identifies these upstream fixed releases:
- Linux 6.1.138 includes the stable-branch fix.
- Linux 6.6.90 includes the stable-branch fix.
- Linux 6.12.28 includes the stable-branch fix.
- Linux 6.14.6 includes the stable-branch fix.
- Linux 6.15-rc5 carried the upstream fix before the final 6.15 release.
The important operational catch is that vendor kernels do not map cleanly to upstream version labels. Ubuntu’s current CVE record, for example, marks its Ubuntu 24.04 LTS
linuxpackage fixed in version
6.8.0-100.100, even though Linux 6.8 is absent from the upstream stable-version list because it is no longer an upstream long-term branch. That is normal vendor backporting, and it means a simple rule such as “every 6.8 kernel is vulnerable” would be wrong.
The same Ubuntu record still lists the base Linux package on Ubuntu 22.04 LTS as vulnerable as of its July 16, 2026 update, while some newer hardware-enable and cloud kernel variants have their own fixed or vulnerable statuses. That split illustrates the real administrative task: identify the installed package flavor and consult the distribution’s advisory, rather than comparing only
uname -rto a public upstream release number.
The Linux kernel CVE team also explicitly cautions against cherry-picking the single corrective commit. Stable fixes are tested as part of a full kernel release, and distribution maintainers commonly include prerequisite changes, build adjustments, and packaging-specific validation. For managed systems, the supported vendor kernel update is the correct remediation path.
Windows systems are outside the affected component
For WindowsForum readers, the distinction is straightforward: Windows 10 and Windows 11 do not use the Linux file and driver path named in CVE-2025-37903. The affected source file belongs to Linux DRM and the AMDGPU kernel driver. An AMD Ryzen laptop or Radeon desktop running Windows can use the same physical dock, display, monitor, and graphics silicon without running this Linux kernel component.
That does not make the advisory irrelevant to mixed estates. Organizations often deploy the same AMD USB-C laptop model across Windows and Linux users, or use Linux for engineering workstations, CI runners, virtual-machine hosts, kiosks, thin clients, and specialized appliances. Hardware inventory alone will overstate exposure; operating-system and kernel-package inventory are what determine it.
Administrators should separate the fleet into three groups:
- Windows-only machines need no action for CVE-2025-37903.
- Linux machines with AMD graphics should be checked for the distribution’s patched kernel package, especially where USB-C docks and multi-display setups are routinely attached and removed.
- Custom kernels, frozen appliance kernels, and end-of-life distribution releases need a source-level or vendor-backport review, because their version strings may not reveal whether the patch is present.
The durable fix has existed upstream since 2025. The remaining exposure in August 2026 is therefore less about waiting for AMD to ship a driver and more about systems that have fallen behind their Linux distribution’s kernel maintenance stream.
