CVE-2026-45897
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Netfilter Counter Reset Race Condition in Linux Kernel

Publication date: 2026-05-27

Last updated on: 2026-05-27

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_counter: serialize reset with spinlock Add a global static spinlock to serialize counter fetch+reset operations, preventing concurrent dump-and-reset from underrunning values. The lock is taken before fetching the total so that two parallel resets cannot both read the same counter values and then both subtract them. A global lock is used for simplicity since resets are infrequent. If this becomes a bottleneck, it can be replaced with a per-net lock later.
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Meta Information
Published
2026-05-27
Last Modified
2026-05-27
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-15
NVD
EUVD
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux kernel *
linux_kernel linux_kernel *
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Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's netfilter nft_counter component. It involves a race condition where concurrent operations to fetch and reset counters could lead to incorrect counter values being read and subtracted. Specifically, without proper serialization, two parallel reset operations might read the same counter values and both subtract them, causing underrunning of values.

The fix involves adding a global static spinlock to serialize the fetch and reset operations, ensuring that only one reset operation can occur at a time. This prevents the race condition and maintains accurate counter values.

Impact Analysis

This vulnerability can cause inaccurate counter values in the netfilter nft_counter feature of the Linux kernel. Specifically, concurrent reset operations could lead to counters being underrun, meaning the counters might report lower values than actual.

Such inaccuracies could impact network monitoring, traffic accounting, or firewall rule statistics that rely on these counters, potentially leading to incorrect data being used for decision-making or analysis.

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