CVE-2023-3777: Use-after-free in Linux kernel's netfilter: nf_tables component

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-09-06 · updated 2026-10-14
Weakness: CWE-416

Description

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. When nf_tables_delrule() is flushing table rules, it is not checked whether the chain is bound and the chain's owner rule can also release the objects in certain circumstances. We recommend upgrading past commit 6eaf41e87a223ae6f8e7a28d6e78384ad7e407f8.

Affected products

Canonical Ubuntu Linux: 14.04, 16.04, 18.04, 20.04, 22.04
Debian Linux: 12.0
Linux kernel: from 5.9 before 5.10.188; from 5.11 before 5.15.123; from 5.16 before 6.1.42; from 6.2 before 6.4.7 — fixed in 5.10.188, 5.15.123, 6.1.42, 6.4.7

How to fix

Upgrade to a fixed version: Linux kernel 5.10.188, 5.15.123, 6.1.42, 6.4.7. Check the vendor advisory for mitigations.

References

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