Medium 5.5Published Sep 11, 2025

CVE-2025-39764netfilter: ctnetlink: remove refcounting in expectation dumpers

Updated under an hour ago (Oct 26, 2026, 2:10 PM ET)

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It affects Linux and 4 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: remove refcounting in expectation dumpers Same pattern as previous patch: do not keep the expectation object alive via refcount, only store a cookie value and then use that as the skip hint for dump resumption. AFAICS this has the same issue as the one resolved in the conntrack dumper, when we do if (!refcount_inc_not_zero(&exp->use)) to increment the refcount, there is a chance that exp == last, which causes a double-increment of the refcount and subsequent memory leak.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from cf6994c2b9812a9f02b99e89df411ffc5db9c779 before b05500444b8eb97644efdd180839a04a706be97c; from cf6994c2b9812a9f02b99e89df411ffc5db9c779 before bada48ad5b0590e318d0f79636ff62a2ef9f4955; from cf6994c2b9812a9f02b99e89df411ffc5db9c779 before 64b7684042246e3238464c66894e30ba30c7e851; from cf6994c2b9812a9f02b99e89df411ffc5db9c779 before 9e5021a906532ca16e2aac69c0607711e1c70b1f; from cf6994c2b9812a9f02b99e89df411ffc5db9c779 before 078d33c95bf534d37aa04269d1ae6158e20082d5; from cf6994c2b9812a9f02b99e89df411ffc5db9c779 before a4d634ded4d3d400f115d84f654f316f249531c9; from cf6994c2b9812a9f02b99e89df411ffc5db9c779 before 1492e3dcb2be3aa46d1963da96aa9593e4e4db5a	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 2.6.23 before 6.16.2; 6.17	NVD

References

References

https://git.kernel.org/stable/c/b05500444b8eb97644efdd180839a04a706be97c
https://git.kernel.org/stable/c/bada48ad5b0590e318d0f79636ff62a2ef9f4955
https://git.kernel.org/stable/c/64b7684042246e3238464c66894e30ba30c7e851
https://git.kernel.org/stable/c/9e5021a906532ca16e2aac69c0607711e1c70b1f
https://git.kernel.org/stable/c/078d33c95bf534d37aa04269d1ae6158e20082d5
https://git.kernel.org/stable/c/a4d634ded4d3d400f115d84f654f316f249531c9	patch
https://git.kernel.org/stable/c/1492e3dcb2be3aa46d1963da96aa9593e4e4db5a	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
https://cert-portal.siemens.com/productcert/html/ssa-457936.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.