Linux Kernel up to 6.18.16/6.19.6/7.0-rc2 nf_tables synchronize_rcu state issue

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.18.16/6.19.6/7.0-rc2. This issue affects the function synchronize_rcu of the component nf_tables. The manipulation results in state issue. This vulnerability is identified as CVE-2026-23272. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.18.16/6.19.6/7.0-rc2. Affected is the function synchronize_rcu of the component nf_tables. The manipulation with an unknown input leads to a state issue vulnerability. CWE is classifying the issue as CWE-371. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: unconditionally bump set->nelems before insertion In case that the set is full, a new element gets published then removed without waiting for the RCU grace period, while RCU reader can be walking over it already. To address this issue, add the element transaction even if set is full, but toggle the set_full flag to report -ENFILE so the abort path safely unwinds the set to its previous state. As for element updates, decrement set->nelems to restore it. A simpler fix is to call synchronize_rcu() in the error path. However, with a large batch adding elements to already maxed-out set, this could cause noticeable slowdown of such batches.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-23272 since 01/13/2026. The exploitability is told to be difficult. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/18/2026).

The vulnerability scanner Nessus provides a plugin with the ID 303181 (Linux Distros Unpatched Vulnerability : CVE-2026-23272), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.17, 6.19.7 or 7.0-rc3 eliminates this vulnerability. Applying the patch 6826131c7674329335ca25df2550163eb8a1fd0c/ccb8c8f3c1127cf34d18c737309897c68046bf21/def602e498a4f951da95c95b1b8ce8ae68aa733a is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (303181), EUVD (EUVD-2026-13607) and CERT Bund (WID-SEC-2026-0809). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Google Container-Optimized OS
• Debian Linux
• Google Cloud Platform
• Amazon Linux 2
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3
• 6.19.4
• 6.19.5
• 6.19.6
• 7.0-rc1
• 7.0-rc2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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