---
id: CVE-2023-54243
title: 'netfilter: ebtables: fix table blob use-after-free'
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…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 <
    9060abce3305ab2354c892c09d5689df51486df5
  - >-
    Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 <
    dbb3cbbf03b3c52cb390fabec357f1e4638004f5
  - >-
    Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 <
    3dd6ac973351308d4117eda32298a9f1d68764fd
  - >-
    Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 <
    cda0e0243bd3c04008fcd37a46b0269fb3c49249
  - >-
    Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 <
    e58a171d35e32e6e8c37cfe0e8a94406732a331f
  - Linux a3bc0f8ea439762aa62d40a295157410498cbea7
  - Linux 8ed40c122919cd79bc3c059e5864e5e7d9d455f0
  - Linux c5e4ef499cfc78de45a4f01b8c557b5964d77c53
  - Linux f34728610b2a8c7b9864f9404f2884c17f6fca5c
  - Linux 8b5740915a9faa8b1fa9166193a33e2a9ae30ec6
  - Linux >= 3.2.60 < 3.3
  - Linux >= 3.4.91 < 3.5
  - Linux >= 3.10.41 < 3.11
  - Linux >= 3.12.21 < 3.13
  - Linux >= 3.14.5 < 3.15
  - Linux 3.15
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:39:46.179216Z'
published: '2025-12-30'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T21:41:43.012Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-54243'
references:
  - url: 'https://git.kernel.org/stable/c/9060abce3305ab2354c892c09d5689df51486df5'
  - url: 'https://git.kernel.org/stable/c/dbb3cbbf03b3c52cb390fabec357f1e4638004f5'
  - url: 'https://git.kernel.org/stable/c/3dd6ac973351308d4117eda32298a9f1d68764fd'
  - url: 'https://git.kernel.org/stable/c/cda0e0243bd3c04008fcd37a46b0269fb3c49249'
  - url: 'https://git.kernel.org/stable/c/e58a171d35e32e6e8c37cfe0e8a94406732a331f'
tags:
  - cve.org
epss: 0.0015
epssPercentile: 0.03742
ingestedAt: '2026-10-15T22:48:25.436Z'
---

## Overview

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.

## Affected

- `Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 < 9060abce3305ab2354c892c09d5689df51486df5`
- `Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 < dbb3cbbf03b3c52cb390fabec357f1e4638004f5`
- `Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 < 3dd6ac973351308d4117eda32298a9f1d68764fd`
- `Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 < cda0e0243bd3c04008fcd37a46b0269fb3c49249`
- `Linux >= c58dd2dd443c26d856a168db108a0cd11c285bf3 < e58a171d35e32e6e8c37cfe0e8a94406732a331f`
- `Linux a3bc0f8ea439762aa62d40a295157410498cbea7`
- `Linux 8ed40c122919cd79bc3c059e5864e5e7d9d455f0`
- `Linux c5e4ef499cfc78de45a4f01b8c557b5964d77c53`
- `Linux f34728610b2a8c7b9864f9404f2884c17f6fca5c`
- `Linux 8b5740915a9faa8b1fa9166193a33e2a9ae30ec6`
- `Linux >= 3.2.60 < 3.3`
- `Linux >= 3.4.91 < 3.5`
- `Linux >= 3.10.41 < 3.11`
- `Linux >= 3.12.21 < 3.13`
- `Linux >= 3.14.5 < 3.15`
- `Linux 3.15`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.