CVE-2023-4244: Use-after-free in Linux kernel's netfilter: nf_tables component

Published Aug 28, 2023
·
Updated

A use-after-free flaw was found in nftables sub-component due to a race problem between set GC and transaction in the Linux Kernel. This flaw could allow a local attacker to crash the system, due to missing call to to nftsetelemmarkbusy causing double deactivation of the element. This vulnerability could even lead to a kernel information leak problem.

Refer: https://lore.kernel.org/netdev/20230810070830.24064-1-pablo@netfilter.org/ https://lore.kernel.org/netdev/20230815223011.7019-1-fw@strlen.de/

Other sources

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

Due to a race condition between nftables netlink control plane transaction and nftset element garbage collection, it is possible to underflow the reference counter causing a use-after-free vulnerability.

We recommend upgrading past commit 3e91b0ebd994635df2346353322ac51ce84ce6d8.

MITRE

Affected Software

8 affected componentsFixes available
redhat/Kernel<6.5
6.5
Linux Linux kernel<6.5
Debian Debian Linux=10.0
IBM Security Verify Governance<=ISVG 10.0.2
IBM Security Verify Governance, Identity Manager Software Stack<=ISVG 10.0.2
IBM Security Verify Governance, Identity Manager Virtual Appliance<=ISVG 10.0.2
IBM Security Verify Governance Identity Manager Container<=ISVG 10.0.2
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.27-1

Remediation

Mitigation

If not needed, disable the ability for unprivileged users to create namespaces. To do this temporarily, do: sudo sysctl -w kernel.unprivileged_userns_clone=0 To disable across reboots, do: echo kernel.unprivileged_userns_clone=0 | \ sudo tee /etc/sysctl.d/99-disable-unpriv-userns.conf

Event History

Sep 6, 2023
CVE Published
via MITRE·01:53 PM
Data Sourced
via MITRE·01:53 PM
DescriptionSeverityWeakness
Jan 20, 2024
Data Sourced
via Launchpad·12:28 AM
Description
Apr 28, 2025
Data Sourced
via Ubuntu·02:14 PM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Debian·02:17 PM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is CVE-2023-4244?

CVE-2023-4244 is a use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component.

2

How can CVE-2023-4244 be exploited?

CVE-2023-4244 can be exploited to achieve local privilege escalation.

3

What is the severity of CVE-2023-4244?

CVE-2023-4244 has a severity rating of 7.8 (high).

4

What software is affected by CVE-2023-4244?

CVE-2023-4244 affects the Linux kernel version 6.5 and below.

5

Is there a fix for CVE-2023-4244?

Yes, a fix for CVE-2023-4244 is available. Please refer to the provided references for more information on the fix.

Contact

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