CVE-2026-46317

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Reassign nested_mmus array behind mmu_lock kvm->arch.nested_mmus[] is walked under kvm->mmu_lock, including from the MMU notifier path (kvm_unmap_gfn_range() -> kvm_nested_s2_unmap()), which can run at any time. kvm_vcpu_init_nested() reallocates the array and frees the old buffer while holding only kvm->arch.config_lock, so such a walker can reference the freed array. Allocate the new array outside of mmu_lock, as the allocation can sleep. Under the lock, copy the existing entries, fix up the back pointers and reassign the array. Free the old buffer after dropping the lock, as kvfree() can sleep as well.

CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/4424dbcb06d68e34e51c019a5781a7dc00731971 https://git.kernel.org/stable/c/70543358fa08e0f7cebc3447c3b70fe97ad7aaa8 https://git.kernel.org/stable/c/918450ad6010df6ecd2efde12a1409e011da22d6

Frequently Asked Questions

What is CVE-2026-46317? +

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Reassign nested_mmus array behind mmu_lock kvm->arch.nested_mmus[] is walked under kvm->mmu_lock, including from the MMU notifier path (kvm_unmap_gfn_range() -> kvm_nested_s2_unmap()), which can run at any time. kvm_vcpu_init_nested() reallocates the array and frees the old buffer while holding only kvm->arch.config_lock, so such a walker can reference the freed array. Allocate the new array outside of mmu_lock, as the allocation can sleep. Under the lock, copy the existing entries, fix up the back pointers and reassign the array. Free the old buffer after dropping the lock, as kvfree() can sleep as well. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-46317? +

CVE-2026-46317 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-46317? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.