Description
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Fix mismatched unlock for DMUB HW lock in HWSS fast path

[Why]
The evaluation for whether we need to use the DMUB HW lock isn't the
same as whether we need to unlock which results in a hang when the
fast path is used for ASIC without FAMS support.

[How]
Store a flag that indicates whether we should use the lock and use
that same flag to specify whether unlocking is needed.
Published: 2026-05-08
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability arises from inconsistent handling of the DMUB hardware lock in the AMD DRM display driver. When the kernel logic for acquiring the lock does not align with the logic for releasing it, the system can block indefinitely during the fast-path operation on AMD ASICs that lack FAMS support. This results in a denial-of-service condition that halts driver activity and can propagate to a complete kernel hang, severely impacting system availability. The flaw is rooted in timing and lock protocol misuse, and in improper synchronization leading to deadlock (CWE-832, CWE-667).

Affected Systems

All Linux systems that run a kernel containing the AMD DRM display driver with DMUB lock support and employ the HWSS fast path are potentially affected. The CVE indicates the Linux kernel as the only vendor, with no version constraints, which implies any kernel build that still contains the pre-fix lock logic is vulnerable.

Risk and Exploitability

The CVE lists a CVSS score of 5.5 and an EPSS score of < 1%, indicating a moderate severity and very low likelihood of exploitation. The vulnerability is not listed in CISA's KEV catalog. Based on the description, it is inferred that an attacker would need local or privileged access to manipulate GPU request paths, so the attack vector is local. The defect can be triggered by manipulating GPU request paths that engage the fast path, and an attacker with local access could potentially cause a system halt. The requirement for driver interaction suggests that exploitation would be environment-specific and likely require elevated permissions or close proximity to the compromised machine.

Generated by OpenCVE AI on May 15, 2026 at 15:56 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the Linux kernel to a version that includes the DMUB lock fix; distribution maintainers typically bundle this patch in their kernel updates.
  • If a kernel upgrade cannot be performed immediately, disable the AMD GPU driver or suspend GPU usage to prevent the fast path from being invoked, thereby avoiding the lock mismatch.
  • If your distribution offers kernel parameters to force the slow legacy path or disable DMUB locking for unsupported ASICs, enable such settings to mitigate the issue until a patch is deployed.
  • Check your distribution’s website or kernel update channel for patches or newer kernel releases that contain the fix.

Generated by OpenCVE AI on May 15, 2026 at 15:56 UTC.

Tracking

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Advisories

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History

Fri, 15 May 2026 13:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-667
Metrics 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'}


Sat, 09 May 2026 03:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-368

Sat, 09 May 2026 00:15:00 +0000


Fri, 08 May 2026 15:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-368

Fri, 08 May 2026 13:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix mismatched unlock for DMUB HW lock in HWSS fast path [Why] The evaluation for whether we need to use the DMUB HW lock isn't the same as whether we need to unlock which results in a hang when the fast path is used for ASIC without FAMS support. [How] Store a flag that indicates whether we should use the lock and use that same flag to specify whether unlocking is needed.
Title drm/amd/display: Fix mismatched unlock for DMUB HW lock in HWSS fast path
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T22:21:59.194Z

Reserved: 2026-05-01T14:12:56.000Z

Link: CVE-2026-43305

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-05-08T14:16:37.813

Modified: 2026-05-15T13:23:19.233

Link: CVE-2026-43305

cve-icon Redhat

Severity :

Publid Date: 2026-05-08T00:00:00Z

Links: CVE-2026-43305 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-15T16:00:03Z

Weaknesses