In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: fix refcount leak on table dump
There is a reference count leak in ctnetlink_dump_table():
if (res < 0) {
nf_conntrack_get(&ct->ct_general); // HERE
cb->args[1] = (unsigned long)ct;
...
While its very unlikely, its possible that ct == last.
If this happens, then the refcount of ct was already incremented.
This 2nd increment is never undone.
This prevents the conntrack object from being released, which in turn
keeps prevents cnet->count from dropping back to 0.
This will then block the netns dismantle (or conntrack rmmod) as
nf_conntrack_cleanup_net_list() will wait forever.
This can be reproduced by running conntrack_resize.sh selftest in a loop.
It takes ~20 minutes for me on a preemptible kernel on average before
I see a runaway kworker spinning in nf_conntrack_cleanup_net_list.
One fix would to change this to:
if (res < 0) {
if (ct != last)
nf_conntrack_get(&ct->ct_general);
But this reference counting isn't needed in the first place.
We can just store a cookie value instead.
A followup patch will do the same for ctnetlink_exp_dump_table,
it looks to me as if this has the same problem and like
ctnetlink_dump_table, we only need a 'skip hint', not the actual
object so we can apply the same cookie strategy there as well.
References
Configurations
Configuration 1 (hide)
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Configuration 2 (hide)
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History
09 Jan 2026, 15:57
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:2.6.18:rc6:*:*:*:*:*:* cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.18:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.18:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:2.6.18:rc5:*:*:*:*:*:* |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| First Time |
Linux
Debian Debian debian Linux Linux linux Kernel |
|
| CWE | NVD-CWE-Other | |
| References | () https://git.kernel.org/stable/c/19b909a4b1452fb97e477d2f08b97f8d04095619 - Patch | |
| References | () https://git.kernel.org/stable/c/30cf811058552b8cd0e98dff677ef3f89d6d34ce - Patch | |
| References | () https://git.kernel.org/stable/c/41462f4cfc583513833f87f9ee55d12da651a7e3 - Patch | |
| References | () https://git.kernel.org/stable/c/586892e341fbf698e7cbaca293e1353957db725a - Patch | |
| References | () https://git.kernel.org/stable/c/962518c6ca9f9a13df099cafa429f72f68ad61f0 - Patch | |
| References | () https://git.kernel.org/stable/c/a2cb4df7872de069f809de2f076ec8e54d649fe3 - Patch | |
| References | () https://git.kernel.org/stable/c/a62d6aa3f31f216b637a4c71b7a8bfc7c57f049b - Patch | |
| References | () https://git.kernel.org/stable/c/de788b2e6227462b6dcd0e07474e72c089008f74 - Patch | |
| References | () https://git.kernel.org/stable/c/e14f72aa66c029db106921d621edcedef68e065b - Patch | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html - Third Party Advisory, Mailing List | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html - Third Party Advisory, Mailing List |
03 Nov 2025, 18:16
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
04 Sep 2025, 16:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-09-04 16:15
Updated : 2026-01-09 15:57
NVD link : CVE-2025-38721
Mitre link : CVE-2025-38721
CVE.ORG link : CVE-2025-38721
JSON object : View
Products Affected
debian
- debian_linux
linux
- linux_kernel
CWE