The vulnerability originates in the Linux kernel’s mincore subsystem, which misidentifies non‑swap memory pages when swap support is disabled but migration or memory‑failure features are enabled. The code checks for swap before verifying that a page is a non‑swap entry, causing a spurious WARN and reporting such pages—migration, hardware‑poisoned, or shmem swap‑in‑error entries—as non‑resident. This manifests as incorrect page‑residency data rather than a direct security breach, but it can affect diagnostics, performance monitoring, and tools that rely on accurate residency information. The weakness is classified as CWE‑393 (Incorrect Default Values).

All Linux kernel builds compiled without swap support (CONFIG_SWAP disabled) but with CONFIG_MIGRATION or CONFIG_MEMORY_FAILURE enabled are affected. The issue exists in every kernel revision prior to the patch that moves the swap guard below the non‑swap entry check, regardless of kernel version. Once the patch is applied the problem is resolved and only true swap entries trigger the WARN.

The CVSS score of 5.5 indicates a medium severity vulnerability, while the EPSS score of <1% reflects a very low probability of exploitation. The flaw does not provide a remote or local attack vector that can compromise confidentiality, integrity, or availability; it only triggers a warning and misreports page residency. No known exploitation path or remote code execution is described. The combination of limited impact and low exploit probability keeps the overall risk low to moderate. The vulnerability is not listed in the CISA KEV catalog.