CVE-2025-71146: netfilter: nf_conncount: fix leaked ct in error paths

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-23 · updated 2026-07-30
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: fix leaked ct in error paths There are some situations where ct might be leaked as error paths are skipping the refcounted check and return immediately. In order to solve it make sure that the check is always called.

Affected products

Linux kernel: from 6.17.13 before 6.18; 6.12.63, 6.18.2, 6.19-rc1 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/08fa37f4c8c59c294e9c18fea2d083ee94074e5a
https://git.kernel.org/stable/c/0b88be7211d21a0d68bb1e56dc805944e3654d6f
https://git.kernel.org/stable/c/2e2a720766886190a6d35c116794693aabd332b6
https://git.kernel.org/stable/c/325eb61bb30790ea27782203a17b007ce1754a67
https://git.kernel.org/stable/c/4bd2b89f4028f250dd1c1625eb3da1979b04a5e8
https://git.kernel.org/stable/c/e1ac8dce3a893641bef224ad057932f142b8a36f
https://git.kernel.org/stable/c/f381a33f34dda9e4023e38ba68c943bca83245e9

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