---
id: CVE-2026-98283
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  KVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid()

  kvmhv_emulate_tlbie_all_lpid() iterates the nested-guest IDR and drops
  mmu_lock before callin…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  KVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid()

  kvmhv_emulate_tlbie_all_lpid() iterates the nested-guest IDR and drops
  mmu_lock before callin…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e3b6b4661527e821ffbe3db83952fdb1e6e47c49 <
    4d8f7b1f586375df8bce23a0909566ad5e852259
  - >-
    Linux >= e3b6b4661527e821ffbe3db83952fdb1e6e47c49 <
    e37fba1ba69385cff2d0e60b371ee19e7d1852d1
  - >-
    Linux >= e3b6b4661527e821ffbe3db83952fdb1e6e47c49 <
    24b634852413229bb8340d908b115c3365f3a247
  - >-
    Linux >= e3b6b4661527e821ffbe3db83952fdb1e6e47c49 <
    fbf69b7d0555ee83c871f58750770f74b7179ad1
  - >-
    Linux >= e3b6b4661527e821ffbe3db83952fdb1e6e47c49 <
    ec2d7a52b3996ae81131617b4afc0af31583c1b4
  - >-
    Linux >= e3b6b4661527e821ffbe3db83952fdb1e6e47c49 <
    51938dfa8a51a4f85328413fca9b6e21f9d2d088
  - Linux 4.20
published: '2026-10-06'
updated: '2026-10-07'
sourceUpdated: '2026-10-07T07:17:08.070'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98283'
references:
  - url: 'https://git.kernel.org/stable/c/24b634852413229bb8340d908b115c3365f3a247'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4d8f7b1f586375df8bce23a0909566ad5e852259'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/51938dfa8a51a4f85328413fca9b6e21f9d2d088'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e37fba1ba69385cff2d0e60b371ee19e7d1852d1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ec2d7a52b3996ae81131617b4afc0af31583c1b4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fbf69b7d0555ee83c871f58750770f74b7179ad1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98283.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98283'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2546507'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98283'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98283'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98283.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00126
epssPercentile: 0.02242
ingestedAt: '2026-10-06T08:50:17.421Z'
cwe:
  - CWE-825
scores:
  nvd: 8.8
  vendor: 7
  cna: 8.8
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

KVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid()

kvmhv_emulate_tlbie_all_lpid() iterates the nested-guest IDR and drops
mmu_lock before calling kvmhv_emulate_tlbie_lpid(), but does not hold a
reference on the kvm_nested_guest pointer obtained from the IDR.  A
concurrent vCPU issuing a single-LPID tlbie (is=2, ric=2) can race
through kvmhv_flush_nested() -> kvmhv_remove_nested() -> idr_remove /
--refcnt -> kvmhv_release_nested() -> kfree(gp) in that window, leaving
the iterating vCPU with a dangling pointer.  The subsequent
mutex_lock(&gp->tlb_lock) and accesses to gp->shadow_pgtable,
gp->shadow_lpid and gp->l1_host all touch freed memory.  The free path
is fully L1-controlled.

Fix this by incrementing gp->refcnt inside the loop before dropping
mmu_lock, mirroring what kvmhv_get_nested() does, and releasing the
reference with kvmhv_put_nested() after the per-guest work completes.
This is the same get/put discipline already used at every other
call site that drops mmu_lock while holding a nested-guest pointer.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · updated 2026-10-10 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98283.json)