CVE-2025-38721

MEDIUM EPSS 5.0%
Published Sep 4, 20259mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Sep 4, 2025 9mo ago
Last Modified Jun 17, 2026 1w ago

Description

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.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
5.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 14

VendorProductVersionRange
linuxlinux_kernel*≥2.6.19  –  <5.4.297
linuxlinux_kernel*≥5.5  –  <5.10.241
linuxlinux_kernel*≥5.11  –  <5.15.190
linuxlinux_kernel*≥5.16  –  <6.1.149
linuxlinux_kernel*≥6.2  –  <6.6.103
linuxlinux_kernel*≥6.7  –  <6.12.43
linuxlinux_kernel*≥6.13  –  <6.15.11
linuxlinux_kernel*≥6.16  –  <6.16.2
linuxlinux_kernel2.6.18any
linuxlinux_kernel2.6.18any
linuxlinux_kernel2.6.18any
linuxlinux_kernel2.6.18any
linuxlinux_kernel6.17any
debiandebian_linux11.0any

References 13

  • cert-portal.siemens.com https://cert-portal.siemens.com/productcert/html/ssa-032379.html
  • cert-portal.siemens.com https://cert-portal.siemens.com/productcert/html/ssa-082556.html
  • git.kernel.org https://git.kernel.org/stable/c/19b909a4b1452fb97e477d2f08b97f8d04095619
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/30cf811058552b8cd0e98dff677ef3f89d6d34ce
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/41462f4cfc583513833f87f9ee55d12da651a7e3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/586892e341fbf698e7cbaca293e1353957db725a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/962518c6ca9f9a13df099cafa429f72f68ad61f0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a2cb4df7872de069f809de2f076ec8e54d649fe3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a62d6aa3f31f216b637a4c71b7a8bfc7c57f049b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/de788b2e6227462b6dcd0e07474e72c089008f74
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e14f72aa66c029db106921d621edcedef68e065b
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
    Mailing ListThird Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
    Mailing ListThird Party Advisory

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/19b909a4b1452fb97e477d2f08b97f8d04095619
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/30cf811058552b8cd0e98dff677ef3f89d6d34ce
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/41462f4cfc583513833f87f9ee55d12da651a7e3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/586892e341fbf698e7cbaca293e1353957db725a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/962518c6ca9f9a13df099cafa429f72f68ad61f0
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a2cb4df7872de069f809de2f076ec8e54d649fe3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a62d6aa3f31f216b637a4c71b7a8bfc7c57f049b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/de788b2e6227462b6dcd0e07474e72c089008f74
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e14f72aa66c029db106921d621edcedef68e065b
    Patch