CVE-2025-39764

netfilter: ctnetlink: remove refcounting in expectation dumpers

MEDIUM
5.5
CVSS Score
Published: September 11, 2025 at 04:52 PM UTC
Updated: October 19, 2026 at 09:10 PM UTC
4 products affected across 2 vendorsLinux KernelSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP FirmwareSiplus S7-1500 CPU 1518-4 Pn /dp MFP Firmware

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.6.23 ≤ v < 6.16.26.176.17 rc1cf6994c2b9812a9f02b99e89df411ffc5db9c779
Vendor states this is fixed in 078d33c95bf534d37aa04269d1ae6158e20082d5 (fixed)
Vendor states this is fixed in 1492e3dcb2be3aa46d1963da96aa9593e4e4db5a (fixed)
Vendor states this is fixed in 64b7684042246e3238464c66894e30ba30c7e851 (fixed)
Vendor states this is fixed in 9e5021a906532ca16e2aac69c0607711e1c70b1f (fixed)
Vendor states this is fixed in a4d634ded4d3d400f115d84f654f316f249531c9 (fixed)
Vendor states this is fixed in b05500444b8eb97644efdd180839a04a706be97c (fixed)
Vendor states this is fixed in bada48ad5b0590e318d0f79636ff62a2ef9f4955 (fixed)
Vendor states this is fixed in 2.6.23 (unaffected)
Vendor states this is fixed in 5.10.253 (unaffected)
Vendor states this is fixed in 5.15.203 (unaffected)
Vendor states this is fixed in 6.1.167 (unaffected)
Vendor states this is fixed in 6.12.78 (unaffected)
Vendor states this is fixed in 6.16.2 (unaffected)
Vendor states this is fixed in 6.17 (unaffected)
Vendor states this is fixed in 6.6.130 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-Other

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