#VU124883 Always-Incorrect Control Flow Implementation in Linux kernel - CVE-2026-31398
Published: April 6, 2026
Vulnerability identifier: #VU124883
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-31398
CWE-ID: CWE-670
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to incorrect pte restoration in folio_unmap_pte_batch() when restoring page table entries for lazyfree folios during reclaim. A local user can trigger a crafted memory-management sequence to cause a denial of service.
The issue can lead to a kernel BUG and crash when a batch contains a mix of writable and non-writable bits, causing writable mappings to be restored incorrectly and breaking anonymous memory copy-on-write semantics.
Remediation
Install security update from vendor's repository.