CVE-2026-89593

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxdf7a6d1f64056aec572162c5d35ed9ff86ece6f3 < a3c65af20cceb7f997847727636b4017326f845daffected
LinuxLinuxdf7a6d1f64056aec572162c5d35ed9ff86ece6f3 < 0f001491e5a2ec69aa9d5dd6b799e5742245f9eaaffected
LinuxLinuxdf7a6d1f64056aec572162c5d35ed9ff86ece6f3 < 5120b1e048d48596ffaec1a8412012a91adba73baffected
LinuxLinux6.9affected
LinuxLinux0 < 6.9unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References