CVE-2025-21740 Information

Description

In the Linux kernel the following vulnerability has been resolved:

KVM: x86/mmu: Ensure NX huge page recovery thread is alive before waking

When waking a VM’s NX huge page recovery thread ensure the thread is actually alive before trying to wake it. Now that the thread is spawned on-demand during KVM_RUN a VM without a recovery thread is reachable via the related module params.

BUG: kernel NULL pointer dereference address: 0000000000000040 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page Hardware name: QEMU Standard PC (Q35 + ICH9 2009) BIOS 0.0.0 02/06/2015 RIP: 0010:vhost_task_wake+0x5/0x10 Call Trace: set_nx_huge_pages+0xcc/0x1e0 [kvm] param_attr_store+0x8a/0xd0 module_attr_store+0x1a/0x30 kernfs_fop_write_iter+0x12f/0x1e0 vfs_write+0x233/0x3e0 ksys_write+0x60/0xd0 do_syscall_64+0x5b/0x160 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f3b52710104 Modules linked in: kvm_intel kvm CR2: 0000000000000040

Reference

https://git.kernel.org/stable/c/2b3928b7c896e5a9fb6b1373924adafe8e01a0c6 https://git.kernel.org/stable/c/43fb96ae78551d7bfa4ecca956b258f085d67c40 https://git.kernel.org/stable/c/974f85f1f7eb7dc7fce0988046e06eeccab576a7