CVE-2025-40300: stato di sfruttamento e disponibilità della patch
CVE-2025-40300 · CVSS 5.5 MEDIUM · EPSS <1%
In the Linux kernel, the following vulnerability has been resolved:
x86/vmscape: Add conditional IBPB mitigation
VMSCAPE is a vulnerability that exploits insufficient branch predictor
isolation between a guest and a userspace hypervisor (like QEMU). Existing
mitigations already protect kernel/KVM from a malicious guest. Userspace
can additionally be protected by flushing the branch predictors after a
VMexit.
Since it is the userspace that consumes the poisoned branch predictors,
conditionally issue an IBPB after a VMexit and before returning to
userspace. Workloads that frequently switch between hypervisor and
userspace will incur the most overhead from the new IBPB.
This new IBPB is not integrated with the existing IBPB sites. For
instance, a task can use the existing speculation control prctl() to
get an IBPB at context switch time. With this implementation, the
IBPB is doubled up: one at context switch and another before running
userspace.
The intent is to integrate and optimize these cases post-embargo.
[ dhansen: elaborate on suboptimal IBPB solution ]
CVE-2025-40300 viene sfruttato?
Non è nel catalogo CISA KEV.
EPSS stima la probabilità di sfruttamento nei prossimi 30 giorni al <1%.
Codice di exploit pubblico: nessuno trovato nelle fonti monitorate.
Quali prodotti e versioni sono interessati?
Nessun elenco di pacchetti interessati registrato qui.