{"id":"CVE-2026-98719","published":"2026-10-18T16:17:25.463","lastModified":"2026-10-19T10:19:36.137","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Nullify \"have run CPUs\" mask pointer when freeing it\n\nNullify have_run_cpus when freeing the mask, particularly in the error path\nof __sev_guest_init(), so that KVM doesn't have to subtly use sev->active\nto track whether or not the mask has been freed.  As pointed out by Sashiko,\nblindly freeing the mask in sev_vm_destroy() results in a double-free if\nthe mask is freed if __sev_guest_init() fails.\n\nThrow the logic in a helper as nullifying the pointer is frustratingly\ndifficult and weird due to have_run_cpus being a single-entry array when\nCPUMASK_OFFSTACK=n.  Deliberately don't use CPUMASK_VAR_NULL, as it's not\ndirectly assignable when the cpumask is on-stack, e.g. requires using a\nlocal variable and a memcpy(), which is beyond ridiculous.  Furthermore,\nwhile clearing the on-stack bitmask is an unnecessary and arguably unwanted\nside effect, KVM absolutely relies on '0' being the \"null\" value given that\nthe struct is zero-allocated.\n\nOpportunistically add an alloc() helper to pair with free(); there are just\nenough call sites to make doing so worthwhile.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/0fbc7fec2242de6c3dcea6de55573c428e820173","tags":[]},{"url":"https://git.kernel.org/stable/c/8abbc76120a74bfba1851bd97528099d715e45c6","tags":[]},{"url":"https://git.kernel.org/stable/c/b1de3ebf59507e0edacaa5cfa2225bc1869e1b63","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}