CVE-2026-89593 — hugetlb: only adjust reservation during unmapping if mapcount is 0
In the Linux kernel, the following vulnerability has been resolved: hugetlb: only adjust reservation during unmapping if mapcount is 0 Since df7a6d1f6405, __unmap_hugepage_ran…
Published: 2026-09-11 · CVSS: 7.1 · CVSS 3.1
In the Linux kernel, the following vulnerability has been resolved: hugetlb: only adjust reservation during unmapping if mapcount is 0 Since df7a6d1f6405, __unmap_hugepage_range can adjust reservations. In the case of folio mapped in both a parent and a child, if the parent unmaps the range first, the reservation adjustment will result in an underflow of the reserved count. Once the child unmaps the range, the count is restored. Change __unmap_hugepage_range() to check the mapcount before adjusting the reservation.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7