CVE-2026-43400 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: May 11, 2026
CBL-Mariner Releases
Vendor-listed releases
6.6.138.1-1
CISA KEVNot listedBased on the latest collected catalog
EPSS0.1%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-43400?
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: add upper bound check on user inputs in signal ioctl
Huge input values in amdgpu_userq_signal_ioctl can lead to a OOM and could be exploited.
So check these input value against AMDGPU_USERQ_MAX_HANDLES which is big enough value for genuine use cases and could potentially avoid OOM.
(cherry picked from commit be267e15f99bc97cbe202cd556717797cdcf79a5)