CVE-2022-49568: KVM: Don't null dereference ops->destroy

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-26 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: Don't null dereference ops->destroy A KVM device cleanup happens in either of two callbacks: 1) destroy() which is called when the VM is being destroyed; 2) release() which is called when a device fd is closed. Most KVM devices use 1) but Book3s's interrupt controller KVM devices (XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during the machine execution. The error handling in kvm_ioctl_create_device() assumes destroy() is always defined which leads to NULL dereference as discovered by Syzkaller. This adds a checks for destroy!=NULL and adds a missing release(). This is not changing kvm_destroy_devices() as devices with defined release() should have been removed from the KVM devices list by then.

Affected products

Linux kernel: before 5.4.210; from 5.5 before 5.10.134; from 5.11 before 5.15.58; from 5.16 before 5.18.15; 5.19-rc1 — fixed in 5.10.134, 5.15.58, 5.18.15, 5.4.210

How to fix

Upgrade to a fixed version: Linux kernel 5.10.134, 5.15.58, 5.18.15, 5.4.210. Check the vendor advisory for mitigations.

References

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