CVE-2026-72292

CVE-2026-72292 · KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory

EPSS 0.2% · Fix available

dpkg-query -W -f='${source:Package} ${binary:Package} ${Version}\n' | awk '$1=="linux"'

dpkg-query -W -f='${source:Package} ${binary:Package} ${Version}\n' | awk '$1=="linux-hwe-edge"'

dpkg-query -W -f='${source:Package} ${binary:Package} ${Version}\n' | awk '$1=="linux-aws-5.0"'

curl -fsSL https://patchfirst.dev/check.sh | sh

This page contains facts from public vulnerability sources. Check the original advisory before updating.

This page shows selected source facts. See the linked advisories for the complete description and affected versions.

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory kvm_s390_get_cmma_bits() allocates its output buffer with vmalloc(), which does not zero the returned pages: values = vmalloc(args->count); In the non-peek (migration) path, dat_get_cmma() reports a byte count spanning from the first to the last dirty page, but __dat_get_cmma_pte() writes values[gfn - start] only for pages whose CMMA dirty bit is set. The walk uses DAT_WALK_IGN_HOLES, so clean and unmapped pages that lie between two dirty pages within the reported span are visited but never store their byte. Those gaps (up to KVM_S390_MAX_BIT_DISTANCE pages each) stay uninitialized yet fall inside [0, count) and are copied out by copy_to_user(), disclosing stale kernel memory to user space. Before the switch to the new gmap implementation the buffer was fully populated for every gfn in the span, so no uninitialized bytes were exposed; the dirty-only walk introduced the leak. Use vzalloc() so the gaps read back as zero.

Published

2026-08-15T05:55:13.248Z

Updated

2026-08-17T05:11:54.937Z

Stack: system

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