The Linux kernel's KVM arm64 code had a vulnerability where the SRCU lock (kvm->srcu) was not consistently acquired during page table walks in fault injection and address translation emulation functions. Specifically, __kvm_at_s12() and __kvm_find_s1_desc_level() called page table walkers without holding the SRCU lock, which is required to guard against concurrent memslot changes. The fix involved acquiring the SRCU lock prior to these table walks, preventing potential race conditions or inconsistent memory state during nested virtualization.

This vulnerability could allow unsafe concurrent memory slot changes during nested virtualization page table walks, potentially leading to memory corruption or instability in virtualized environments on arm64 architectures. However, there are no known exploits in the wild, and the attack vector requires local access with high complexity and privileges.

A fix is available in Linux kernel versions 7.0.0-28.28.1 and later. Users should upgrade to a patched kernel version to remediate this vulnerability. No additional mitigations are indicated by the vendor advisory.