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Fencer Vulns
high 7.1

CVE-2026-31568 json

s390/mm: Add missing secure storage access fixups for donated memory

published 2026-04-24 6 mo ago modified 2026-11-05 3 d ago also EUVD-2026-25461

cvss
7.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

s390/mm: Add missing secure storage access fixups for donated memory

There are special cases where secure storage access exceptions happen in a kernel context for pages that don't have the PG_arch_1 bit set. That bit is set for non-exported guest secure storage (memory) but is absent on storage donated to the Ultravisor since the kernel isn't allowed to export donated pages.

Prior to this patch we would try to export the page by calling arch_make_folio_accessible() which would instantly return since the arch bit is absent signifying that the page was already exported and no further action is necessary. This leads to secure storage access exception loops which can never be resolved.

With this patch we unconditionally try to export and if that fails we fixup.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.18.21, 6.19.11, 7.0
  • linux Debian 14 6.19.11-1

debian advisories DEBIAN-CVE-2026-31568

  • linux-nvidia-tegra Ubuntu 24.04 LTS 6.8.0-1035.38

ubuntu advisories UBUNTU-CVE-2026-31568

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

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.73.2
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.73.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.73.2
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.73.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.73.2
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.73.2
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.73.2
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.73.2.150700.17.41.4

suse advisories SUSE-SU-2026:3166-1SUSE-SU-2026:3130-1SUSE-SU-2026:22048-1SUSE-SU-2026:22087-1SUSE-SU-2026:22076-1SUSE-SU-2026:22043-1

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-2026-31568 updated cvss 5.5

kernel: s390/mm: Add missing secure storage access fixups for donated memory

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • 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
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
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.