SB20260424273 - Race condition in Linux kernel mm

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-31456)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 6.8 [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]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a race condition in walk_pmd_range() when walking page tables during concurrent PUD splitting and refault handling. A local user can trigger concurrent memory-management operations to cause a denial of service.

An example scenario involves reading numa_maps of a process while VFIO-PCI is setting up DMA on a large BAR for that process.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/38ec58670a0c5fc1edabdeccd857e586b7b3f318
• https://git.kernel.org/stable/c/3b89863c3fa482912911cd65a12a3aeef662c250
• https://git.kernel.org/stable/c/9bbbebd94dd5be25ec8c899d46ef01b33d5d22c0