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Fencer Vulns
medium 6.7

CVE-2023-21400 json

In multiple functions of io_uring.c, there is a possible kernel memory corruption due to improper locking.

published 2023-07-12 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-25568

cvss
6.7
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

In multiple functions of io_uring.c, there is a possible kernel memory corruption due to improper locking. This could lead to local escalation of privilege in the kernel with System execution privileges needed. User interaction is not needed for exploitation.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.18.2-1

debian advisories DEBIAN-CVE-2023-21400

  • linux Ubuntu 20.04 LTS 5.4.0-205.225
  • linux Ubuntu 22.04 LTS 5.15.0-82.91
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1139.149
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1043.48
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1142.151
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1040.48
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1040.45
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1085.90

ubuntu advisories UBUNTU-CVE-2023-21400

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-rt SLE Micro 5.2, SLE Micro 5.1 5.3.18-150300.141.1
  • kernel-default SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE Live Patching 15 SP2 +2 more 5.3.18-150200.24.163.1
  • dtb-aarch64 openSUSE Leap 15.4 5.3.18-150300.59.133.1
  • kernel-64kb SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS, SLE High Performance Computing 15 SP3-ESPOS +1 more 5.3.18-150300.59.133.1
  • kernel-syms SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +2 more 5.3.18-150300.59.133.1
  • kernel-source SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +4 more 5.3.18-150300.59.133.1
  • kernel-default SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Micro 5.2 +8 more 5.3.18-150300.59.133.1
  • kernel-preempt SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS +4 more 5.3.18-150300.59.133.1

suse advisories SUSE-SU-2023:3785-1SUSE-SU-2023:3687-1SUSE-SU-2023:3684-1SUSE-SU-2023:3377-1SUSE-SU-2023:3376-1SUSE-SU-2023:3318-1

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-2023-21400 updated cvss 7.0

kernel: io_uring: io_defer_entry object double free vulnerability

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more 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
    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

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com http://www.openwall.com/lists/oss-security/2023/07/19/2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.7 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Google Android

Classification

Weakness

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.