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CVE-2026-31456 Linux CVE debrief

A race condition vulnerability was discovered in the Linux kernel, specifically in the `walk_pud_range()` function. This vulnerability occurs when a PUD entry is being split concurrently with a refault operation on the PUD leaf entry. This can lead to a kernel BUG and potentially allow an attacker to crash the system. The vulnerability has a CVSS score of 4.7 and is classified as MEDIUM severity.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 4.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-22
Original CVE updated
2026-06-05
Advisory published
2026-04-22
Advisory updated
2026-06-05

Who should care

Users of Linux kernel versions 6.12, 6.19, and 7.0 (up to rc5) should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability is caused by a race condition between concurrent split and refault operations in the `walk_pud_range()` function. This can lead to a kernel BUG and potentially allow an attacker to crash the system. The fix involves validating the PUD entry in `walk_pmd_range()` using a stable snapshot (`pudp_get()`).

Defensive priority

MEDIUM

Recommended defensive actions

  • Apply the patches provided by the Linux kernel maintainers [ref-4], [ref-5], [ref-6].
  • Update to a Linux kernel version that includes the fix, such as 6.18.21, 6.19.11, or later.

Evidence notes

The vulnerability was discovered and reported by an unknown researcher. The fix was provided by the Linux kernel maintainers.

Official resources

CVE-2026-31456 was published on 2026-04-22T14:16:40.203Z and modified on 2026-06-05T17:40:38.510Z.