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Fencer Vulns
no cvss —

CVE-2026-72292 json

KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory

published 2026-08-15 2 mo ago modified 2026-08-17 2 mo ago also EUVD-2026-59191

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 7.1.5, 7.2
  • linux Debian 14 7.1.5-1

debian advisories DEBIAN-CVE-2026-72292

  • linux Ubuntu 26.04 LTS 7.0.0-38.38
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1008.9
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1015.15
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-38.38.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1013.13

ubuntu advisories UBUNTU-CVE-2026-72292

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-72292 updated cvss 5.5

kernel: KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.