CVE-2026-89754

A flaw was found in the Linux kernel's memory management (mm/pagewalk) component. An issue in the walk_pmd_range() function, where a stale walk->action state is not properly reset, can lead to duplicate walk callbacks. A local attacker could exploit this to trigger an out-of-bounds write, potentially causing memory corruption and system instability.

This vulnerability is rated with an Important severity because an authenticated local user could induce kernel memory corruption or system instability through an out-of-bounds slab write. However, Red Hat Enterprise Linux is not affected because the upstream changes that introduced this faulty page-table traversal logic are not present in supported kernels. Exploitation requires triggering memory query interfaces during concurrent unmapping operations, which only reaches the vulnerable condition in kernels containing the problematic upstream refault commits.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.