CVE-2025-39764
netfilter: ctnetlink: remove refcounting in expectation dumpers
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.
INFO
Published Date :
Sept. 11, 2025, 5:15 p.m.
Last Modified :
Sept. 11, 2025, 5:15 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest version.
- Apply the provided patch for netfilter: ctnetlink.
- Review conntrack dumper logic for similar issues.
- Ensure proper refcount management in related components.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-39764.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/1492e3dcb2be3aa46d1963da96aa9593e4e4db5a | |
| https://git.kernel.org/stable/c/a4d634ded4d3d400f115d84f654f316f249531c9 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-39764 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-39764
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-39764 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-39764 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 11, 2025
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/1492e3dcb2be3aa46d1963da96aa9593e4e4db5a Added Reference https://git.kernel.org/stable/c/a4d634ded4d3d400f115d84f654f316f249531c9