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Fencer Vulns
high 7.8

CVE-2026-23437 json

net: shaper: protect late read accesses to the hierarchy

published 2026-04-03 7 mo ago modified 2026-10-19 20 d ago also EUVD-2026-18678

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

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

net: shaper: protect late read accesses to the hierarchy

We look up a netdev during prep of Netlink ops (pre- callbacks) and take a ref to it. Then later in the body of the callback we take its lock or RCU which are the actual protections.

This is not proper, a conversion from a ref to a locked netdev must include a liveness check (a check if the netdev hasn't been unregistered already). Fix the read cases (those under RCU). Writes needs a separate change to protect from creating the hierarchy after flush has already run.

Patch / fix

  • Linux Linux 6.18.20, 6.19.10, 7.0
  • linux Debian 14 6.19.10-1

debian advisories DEBIAN-CVE-2026-23437

  • kernel-livepatch-SLE16_Update_10 SLES for SAP applications 16.0, SLES 16.0 2-160000.1.1
  • kernel-livepatch-SLE16_Update_11 SLES for SAP applications 16.0, SLES 16.0 2-160000.1.1
  • kernel-livepatch-SLE16_Update_8 SLES for SAP applications 16.0, SLES 16.0 3-160000.1.1
  • kernel-livepatch-SLE16_Update_9 SLES for SAP applications 16.0, SLES 16.0 2-160000.1.1
  • kernel-syms Linux Micro Extras 6.2 6.12.0-160000.33.1
  • kernel-obs-build Linux Micro Extras 6.2 6.12.0-160000.33.1

suse advisories SUSE-SU-2026:22037-1SUSE-SU-2026:22036-1SUSE-SU-2026:22034-1SUSE-SU-2026:22029-1SUSE-SU-2026:21834-1

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-2026-23437 updated cvss 5.5

kernel: net: shaper: protect late read accesses to the hierarchy

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • 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 kernel-rt, kernel-rt-selftests-internal
    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
total
Assessed
24 d ago

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.