CVE-2026-68428

CVE Details

Release Date:	2026-08-10
Impact:	Low	What is this?

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Fix use-after-free on vendor module reload mmu_destroy_caches() destroys pte_list_desc_cache and mmu_page_header_cache, but leaves both pointers unchanged. The pointers live in kvm.ko, and therefore survive when a vendor module is unloaded while kvm.ko remains loaded. If creation of pte_list_desc_cache fails during a subsequent vendor module load, its assignment sets pte_list_desc_cache to NULL and the error path calls mmu_destroy_caches(). mmu_page_header_cache still points to the cache destroyed during the preceding vendor module unload. Passing that stale pointer to kmem_cache_destroy() causes a slab use-after-free. Reproduce the issue on a v7.1.3 kernel with CONFIG_KASAN=y, CONFIG_KASAN_GENERIC=y, CONFIG_KVM=m, and CONFIG_KVM_INTEL=m. A one-shot test hook forces pte_list_desc_cache to NULL on the second invocation of kvm_mmu_vendor_module_init(): 1. Load kvm.ko and kvm-intel.ko, creating both caches. 2. Unload only kvm_intel, leaving kvm.ko loaded. 3. Reload kvm_intel and force initialization through the -ENOMEM path. KASAN reports: BUG: KASAN: slab-use-after-free in kvm_mmu_vendor_module_init+0x5b/0x170 [kvm] ... kmem_cache_destroy+0x21/0x1d0 kvm_mmu_vendor_module_init+0x5b/0x170 [kvm] ... Allocated by task 16817: __kmem_cache_create_args+0x12c/0x3b0 __kmem_cache_create.constprop.0+0xb6/0xf0 [kvm] kvm_mmu_vendor_module_init+0x13b/0x170 [kvm] ... Freed by task 16820: kmem_cache_destroy+0x117/0x1d0 kvm_mmu_vendor_module_exit+0x21/0x30 [kvm] Clear both pointers immediately after destroying their caches so that the stored state reflects the caches' lifetime and repeated cleanup is safe. With the fix applied, the same injected vendor module reload fails with -ENOMEM as expected and produces no KASAN report.

See more information about CVE-2026-68428 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	5.5
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (kernel-uek)	ELSA-2026-500248	2026-09-04
Oracle Linux version 8 (kernel-uek)	ELSA-2026-500249	2026-09-04
Oracle Linux version 9 (kernel-uek)	ELSA-2026-500248	2026-09-04
Oracle Linux version 9 (kernel-uek)	ELSA-2026-500249	2026-09-04