CVE-2026-89593

Published: September 15, 2026Last modified: September 15, 2026

Description

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.

Severity score breakdown

Status

References

• https://git.kernel.org/stable/c/0f001491e5a2ec69aa9d5dd6b799e5742245f9ea
• https://git.kernel.org/stable/c/5120b1e048d48596ffaec1a8412012a91adba73b
• https://git.kernel.org/stable/c/a3c65af20cceb7f997847727636b4017326f845d
• https://git.kernel.org/stable/c/b0b1b9ca80b795ed2223e76dd787db7067121fb9