In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()
ctnetlink_dump_exp_ct() stores a conntrack pointer in cb->data for the
netlink dump callback ctnetlink_exp_ct_dump_table(), but drops the
conntrack reference immediately after netlink_dump_start(). When the
dump spans multiple rounds, the second recvmsg() triggers the dump
callback which dereferences the now-freed conntrack via nfct_help(ct),
leading to a use-after-free on ct->ext.
The bug is that the netlink_dump_control has no .start or .done
callbacks to manage the conntrack reference across dump rounds. Other
dump functions in the same file (e.g. ctnetlink_get_conntrack) properly
use .start/.done callbacks for this purpose.
Fix this by adding .start and .done callbacks that hold and release the
conntrack reference for the duration of the dump, and move the
nfct_help() call after the cb->args[0] early-return check in the dump
callback to avoid dereferencing ct->ext unnecessarily.
BUG: KASAN: slab-use-after-free in ctnetlink_exp_ct_dump_table+0x4f/0x2e0
Read of size 8 at addr ffff88810597ebf0 by task ctnetlink_poc/133
CPU: 1 UID: 0 PID: 133 Comm: ctnetlink_poc Not tainted 7.0.0-rc2+ #3 PREEMPTLAZY
Call Trace:
<TASK>
ctnetlink_exp_ct_dump_table+0x4f/0x2e0
netlink_dump+0x333/0x880
netlink_recvmsg+0x3e2/0x4b0
? aa_sk_perm+0x184/0x450
sock_recvmsg+0xde/0xf0
Allocated by task 133:
kmem_cache_alloc_noprof+0x134/0x440
__nf_conntrack_alloc+0xa8/0x2b0
ctnetlink_create_conntrack+0xa1/0x900
ctnetlink_new_conntrack+0x3cf/0x7d0
nfnetlink_rcv_msg+0x48e/0x510
netlink_rcv_skb+0xc9/0x1f0
nfnetlink_rcv+0xdb/0x220
netlink_unicast+0x3ec/0x590
netlink_sendmsg+0x397/0x690
__sys_sendmsg+0xf4/0x180
Freed by task 0:
slab_free_after_rcu_debug+0xad/0x1e0
rcu_core+0x5c3/0x9c0
References
Configurations
Configuration 1 (hide)
|
History
26 May 2026, 14:38
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://git.kernel.org/stable/c/04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56 - Patch | |
| References | () https://git.kernel.org/stable/c/5cb81eeda909dbb2def209dd10636b51549a3f8a - Patch | |
| References | () https://git.kernel.org/stable/c/9821b47f669eb82791fa0b1a6ebaf9aa219bea72 - Patch | |
| References | () https://git.kernel.org/stable/c/bdf2724eefd4455a66863abb025bab8d3aa98c57 - Patch | |
| References | () https://git.kernel.org/stable/c/cd541f15b60e2257441398cf495d978f816d09f8 - Patch | |
| References | () https://git.kernel.org/stable/c/d8cd0efbccc5cfb0a80da744a7da76e1333ab925 - Patch | |
| References | () https://git.kernel.org/stable/c/f025171feef2ac65663d7986f1d5ff0c28d6b2a9 - Patch | |
| References | () https://git.kernel.org/stable/c/f04cc86d59906513d2d62183b882966fc0ae0390 - Patch | |
| First Time |
Linux
Linux linux Kernel |
|
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* |
|
| CWE | CWE-416 |
27 Apr 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
18 Apr 2026, 09:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
03 Apr 2026, 16:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-03 16:16
Updated : 2026-05-26 14:38
NVD link : CVE-2026-23458
Mitre link : CVE-2026-23458
CVE.ORG link : CVE-2026-23458
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free