CVE-2023-4015 Use-after-free in Linux kernel's netfilter: nf_tables component

What is CVE-2023-4015?

CVE-2023-4015 is a high-severity use after free vulnerability in Debian Debian Linux, published on 6 Sep 2023. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation.

On an error when building a nftables rule, deactivating immediate expressions in nft_immediate_deactivate() can lead unbinding the chain and objects be deactivated but later used.

We recommend upgrading past commit 0a771f7b266b02d262900c75f1e175c7fe76fec2.

Weakness: CWE-416

Which versions are affected by CVE-2023-4015?

It affects 2 products.

Products include Debian Debian Linux, Linux kernel.

How do I fix CVE-2023-4015?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2023-4015 being exploited?

There is no known exploitation of CVE-2023-4015 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-28675, DEBIAN-CVE-2023-4015, GHSA-5m5v-w78j-286f, UBUNTU-CVE-2023-4015.