Josh Poimboeuf

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** A vulnerability in the Linux kernel has been resolved, specifically related to KVM: VMX. The issue concerns preventing RSB underflow before vmenter on VMX. There is a potential risk associated with balanced returns between the time the guest's SPEC CTRL value is written and the vmenter, particularly in the event of an NMI with a deep call stack. To address this, the fix prevents any returns between the SPEC CTRL write and the vmenter. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.