CVE-2024-35801

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue is related to the use of memory after it has been freed in the Linux kernel, specifically in the x86/fpu component. This can lead to a crash of the kernel when the xfd update state() function fails to update the MSR IA32 XFD, resulting in XRSTOR raising a #NM in kernel space. The problem arises because the per CPU variable xfd state is not reset when MSR IA32 XFD is reset to the init fpstate.xfd on CPU hotplug, bringing them out of sync.

Recommendations To fix this issue, introduce xfd set state() to write xfd state together with MSR IA32 XFD, and use it in all places that set MSR IA32 XFD. As a temporary workaround, consider disabling the xfd update state() function until a patch is available. Restrict access to the vulnerable x86/fpu component to minimize the risk of exploitation. Avoid using the xfd state variable in the affected kernel space until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.