CVE-2023-54241
NULL Pointer Dereference in Linux Kernel MIPS KVM Causes Crash
Publication date: 2025-12-30
Last updated on: 2025-12-30
Assigner: kernel.org
Description
Description
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
| linux | linux_kernel | 6.4.0-rc3 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a NULL pointer dereference in the Linux kernel's MIPS KVM (Kernel-based Virtual Machine) subsystem. It occurs after a specific commit removed support for KVM_TE, which caused the vcpu->arch.cop0 pointer to become NULL when creating a KVM guest. This leads to a kernel crash (NULL pointer dereference) when attempting to start a KVM guest with MIPS VZ extensions.
How can this vulnerability impact me? :
The vulnerability can cause a kernel crash when creating or running a KVM guest on MIPS architecture, leading to denial of service. This could disrupt virtual machine operations and potentially affect system stability and availability.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
You can detect this vulnerability by monitoring your system logs for kernel oops messages related to KVM on MIPS architectures. Specifically, look for NULL pointer dereference errors when creating a KVM guest, with log entries similar to: 'CPU Unable to handle kernel paging request at virtual address 0000000000000300' and call traces involving 'kvm_vz_vcpu_setup'. Checking dmesg or /var/log/kern.log for such messages can help identify the issue. Example command: sudo dmesg | grep -i 'kvm_vz_vcpu_setup' or sudo journalctl -k | grep -i 'kvm_vz_vcpu_setup'.
What immediate steps should I take to mitigate this vulnerability?
The immediate mitigation is to update your Linux kernel to a version that includes the fix for this vulnerability, which involves correcting the NULL pointer dereference in the KVM MIPS code. Until then, avoid creating KVM guests on affected MIPS systems to prevent triggering the NULL pointer dereference. Monitoring for kernel crashes and applying kernel patches or updates as soon as they become available is recommended.