Out-of-bounds read in Linux kernel - CVE-2026-64186
Published: July 20, 2026
Vulnerability identifier: #VU138428
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-64186
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to perform an out-of-bounds memory access.
The vulnerability exists due to an out-of-bounds access in AMD IOMMU debugfs handlers when parsing user-supplied debugfs offset values. A local user can provide a sufficiently large value that becomes negative to perform an out-of-bounds memory access.
The issue affects the iommu_mmio_write() and iommu_capability_write() paths in the AMD IOMMU debugfs interface.
How to mitigate CVE-2026-64186
Install security update from vendor's repository.