A flaw in the Linux kernel’s KVM SVM module causes the virtual machine control block’s TLB flush settings to be lost when a VMRUN call fails. As a result, subsequent successful VMRUN operations may either omit required TLB flushes or perform unnecessary flushes of all ASIDs, leading to stale memory translations or performance degradation. The flaw does not provide a direct path to code execution, but it can be used by a guest to trigger repeated full ASID flushes, potentially exhausting host resources and degrading overall cloud or virtual machine performance. This weakness is classified as CWE‑459, involving improper handling of uninitialized data, and results in a denial‑of‑service condition for other guests running on the same host.

The vulnerability affects Linux kernel hosts that run KVM with AMD’s Secure Virtual Machine (SVM) extensions. The advisory does not specify a particular kernel version, so any host running an unpatched KVM SVM implementation may be vulnerable. Distribution‑specific version information is not provided.

The CVSS score of 7.8 indicates high severity. The EPSS score of <1% indicates a very low likelihood that exploitation will occur in the wild. The vulnerability is not listed in the CISA KEV catalog. According to the description, the likely attack vector is a guest operating system running inside a KVM VM on an AMD processor that can trigger a VMRUN failure; the guest can then repeatedly induce full ASID flushes. This behaviour can exhaust host resources and degrade performance for other guests, effectively causing a denial‑of‑service condition on the host. While there is no evidence of active exploitation, the combination of high impact and the availability of an internal attack surface warrants immediate attention.