CVE-2023-54035: netfilter: nf_tables: fix underflow in chain reference counter

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-24 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: fix underflow in chain reference counter Set element addition error path decrements reference counter on chains twice: once on element release and again via nft_data_release(). Then, d6b478666ffa ("netfilter: nf_tables: fix underflow in object reference counter") incorrectly fixed this by removing the stateful object reference count decrement. Restore the stateful object decrement as in b91d90368837 ("netfilter: nf_tables: fix leaking object reference count") and let nft_data_release() decrement the chain reference counter, so this is done only once.

Affected products

Linux kernel: from 4.19.316 before 4.20; from 5.4.262 before 5.5; from 5.10.188 before 5.11; from 5.15.121 before 5.16; from 6.3.10 before 6.4; 6.4 — fixed in 4.20, 5.11, 5.16, 5.5, 6.4, 6.5

How to fix

Upgrade to a fixed version: Linux kernel 4.20, 5.11, 5.16, 5.5. Check the vendor advisory for mitigations.

References

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