In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: keyop: use mmu_lock to read gmap->asce
Every other dat_* consumer in this file (kvm_s390_get_skeys,
set_skeys, get_cmma_bits, set_cmma_bits, MEM_CLR_CMMA,
kvm_s390_fixup_prefix, kvm_test_age_gfn, kvm_age_gfn) reads
kvm->arch.gmap->asce *inside* the mmu_lock read-side. keyop is the only
outlier.
gmap->asce is mutated under write_lock(mmu_lock) by gmap_set_limit()
and keyop might use a stale asce value for walking as KVM_S390_KEYOP
and KVM_S390_VM_MEM_LIMIT_SIZE can run concurrently. This can result
in memory corruption.
CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).
No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table