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Fencer Vulns
medium 5.5

CVE-2023-23586 json

Use after free in io_uring in the Linux Kernel

published 2023-02-17 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-27686

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

Due to a vulnerability in the io_uring subsystem, it is possible to leak kernel memory information to the user process. timens_install calls current_is_single_threaded to determine if the current process is single-threaded, but this call does not consider io_uring's io_worker threads, thus it is possible to insert a time namespace's vvar page to process's memory space via a page fault. When this time namespace is destroyed, the vvar page is also freed, but not removed from the process' memory, and a next page allocated by the kernel will be still available from the user-space process and can leak memory contents via this (read-only) use-after-free vulnerability. We recommend upgrading past version 5.10.161 or commit  788d0824269bef539fe31a785b1517882eafed93 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/io_uring

Patch / fix

  • linux linux_kernel 5.10.161
  • linux Debian 14, Debian 13, Debian 12 5.14.6-1

debian advisories DEBIAN-CVE-2023-23586

  • kernel-syms SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +1 more 5.3.18-150200.24.154.1
  • kernel-source SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +1 more 5.3.18-150200.24.154.1
  • kernel-default SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE Live Patching 15 SP2 +3 more 5.3.18-150200.24.154.1
  • kernel-preempt SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +1 more 5.3.18-150200.24.154.1
  • kernel-obs-build SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +1 more 5.3.18-150200.24.154.1
  • kernel-default-base SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +1 more 5.3.18-150200.24.154.1.150200.9.75.1
  • dtb-aarch64 openSUSE Leap 15.4 5.3.18-150300.59.124.1
  • kernel-64kb SLES 15 SP3-LTSS, SLE High Performance Computing 15 SP3-LTSS, SLE High Performance Computing 15 SP3-ESPOS +1 more 5.3.18-150300.59.124.1

suse advisories SUSE-SU-2023:2651-1SUSE-SU-2023:2611-1SUSE-SU-2023:2502-1

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-2023-23586 updated cvss 5.5

kernel: io_uring: read use-after-free can lead to kernel memory leak

  • 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
19 mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected products

  • Linux Linux Kernel

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.