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Fencer Vulns
high 7.8

CVE-2023-54243 json

netfilter: ebtables: fix table blob use-after-free

published 2025-12-30 10 mo ago modified 2026-10-15 24 d ago also EUVD-2023-60398

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 4%
public exploits
0
none known

Summary

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

netfilter: ebtables: fix table blob use-after-free

We are not allowed to return an error at this point. Looking at the code it looks like ret is always 0 at this point, but its not.

t = find_table_lock(net, repl->name, &ret, &ebt_mutex);

... this can return a valid table, with ret != 0.

This bug causes update of table->private with the new blob, but then frees the blob right away in the caller.

Syzbot report:

BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 Read of size 4 at addr ffffc90005425000 by task kworker/u4:4/74 Workqueue: netns cleanup_net Call Trace: kasan_report+0xbf/0x1f0 mm/kasan/report.c:517 __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613 ...

ip(6)tables appears to be ok (ret should be 0 at this point) but make this more obvious.

Patch / fix

  • Linux Linux 3.3, 3.5, 3.11, 3.13, 3.15, 5.10.173, 5.15.100, 6.1.18, 6.2.5, 6.3
  • linux Debian 14, Debian 13, Debian 12 6.1.20-1

debian advisories DEBIAN-CVE-2023-54243

  • linux Ubuntu 22.04 LTS 5.15.0-79.86
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1042.47
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1039.47
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1039.44
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1035.38
  • linux-kvm Ubuntu 22.04 LTS 5.15.0-1039.44
  • linux-azure Ubuntu 22.04 LTS 5.15.0-1045.52
  • linux-gkeop Ubuntu 22.04 LTS 5.15.0-1025.30

ubuntu advisories UBUNTU-CVE-2023-54243

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 SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS, SLE High Performance Computing 15 SP4-ESPOS 5.14.21-150400.24.194.1
  • kernel-syms SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.194.1
  • kernel-source SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.194.1
  • kernel-default SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +5 more 5.14.21-150400.24.194.1
  • kernel-obs-build SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.194.1
  • kernel-default-base SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 5.14.21-150400.24.194.1.150400.24.98.3
  • kernel-rt SLE Micro 5.5 5.14.21-150500.13.121.1
  • kernel-source-rt SLE Micro 5.5 5.14.21-150500.13.121.1

suse advisories SUSE-SU-2026:0617-1SUSE-SU-2026:0496-1SUSE-SU-2026:0474-1SUSE-SU-2026:0473-1SUSE-SU-2026:0411-1SUSE-SU-2026:0369-1

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-2023-54243 updated cvss 5.3

kernel: netfilter: ebtables: fix table blob use-after-free

  • 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 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
    affected: no fix available “Fix deferred”
  • 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
total
Assessed
24 d ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% 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

Affected products

  • Linux Linux

Classification

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.