Improper Initialization in Linux kernel - CVE-2026-63950
Published: July 20, 2026
Vulnerability identifier: #VU138703
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-63950
CWE-ID: CWE-665
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 cause a denial of service.
The vulnerability exists due to improper initialization in try_to_unmap_one() in mm/rmap.c when reclaiming a lazyfree anonymous folio with device-exclusive page table entries. A local user can trigger reclaim after arranging the affected memory state to cause a denial of service.
Exploitation requires a sequence involving a MAP_ANONYMOUS | MAP_DROPPABLE mapping, MADV_FREE, and making the last page device-exclusive via HMM_DMIRROR_EXCLUSIVE.
How to mitigate CVE-2026-63950
Install security update from vendor's repository.