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Fencer Vulns
high 7.3

CVE-2023-53205 json

KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler

published 2025-09-15 13 mo ago modified 2026-10-15 24 d ago also EUVD-2023-59878

cvss
7.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

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

KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler

We do check for target CPU == -1, but this might change at the time we are going to use it. Hold the physical target CPU in a local variable to avoid out-of-bound accesses to the cpu arrays.

Patch / fix

  • Linux Linux 5.15.121, 6.1.39, 6.4.4, 6.5
  • linux Debian 12 6.1.52-1
  • linux Debian 14, Debian 13 6.4.4-1

debian advisories DEBIAN-CVE-2023-53205

  • linux Ubuntu 22.04 LTS 5.15.0-86.96
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1047.52
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1044.52
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1044.49
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1040.43
  • linux-kvm Ubuntu 22.04 LTS 5.15.0-1044.49
  • linux-azure Ubuntu 22.04 LTS 5.15.0-1049.56
  • linux-gkeop Ubuntu 22.04 LTS 5.15.0-1030.35

ubuntu advisories UBUNTU-CVE-2023-53205

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 RHEL 8 4.18.0-553.el8_10
  • perf RHEL 8 4.18.0-553.el8_10
  • bpftool RHEL 8 4.18.0-553.el8_10
  • kernel-core RHEL 8 4.18.0-553.el8_10
  • kernel-tools RHEL 8 4.18.0-553.el8_10
  • python3-perf RHEL 8 4.18.0-553.el8_10
  • kernel-modules RHEL 8 4.18.0-553.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.el8_10

red hat advisories RHSA-2024:3138RHSA-2023:6583

  • kernel-rt Real Time Module 15 SP7 6.4.0-150700.7.22.1
  • kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.22.1
  • kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.22.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.18.1
  • kernel-syms-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.18.1
  • kernel-source-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.18.1
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.22.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.22.1

suse advisories SUSE-SU-2025:4141-1SUSE-SU-2025:4132-1SUSE-SU-2025:4057-1SUSE-SU-2025:20870-1SUSE-SU-2025:3761-1SUSE-SU-2025:20898-1

  • kernel Rocky Linux 8 4.18.0-553.123.1.el8_10.cloud.0.1

rocky linux advisories RXSA-2024:3138

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-2023-53205 updated cvss 5.3

kernel: KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler

  • 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 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.el8_10, kernel 4.18.0-553.el8_10, bpftool 4.18.0-553.el8_10, kernel-core 4.18.0-553.el8_10, kernel-tools 4.18.0-553.el8_10, python3-perf 4.18.0-553.el8_10, +15 more Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.el8_10
    fixed: vendor fix RHSA-2024:3138
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, python-perf, kernel-kdump, kernel-tools, +3 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
24 d ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.