high
7.8
CWE
416
Advisory Published
Updated

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

First published: Wed Sep 06 2023(Updated: )

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.

Credit: cve-coordination@google.com cve-coordination@google.com cve-coordination@google.com

Affected SoftwareAffected VersionHow to fix
redhat/Kernel<6.5
6.5
Linux Kernel<5.9.0
Linux Kernel>=6.0<6.5
Debian GNU/Linux=12.0
debian/linux
5.10.223-1
5.10.226-1
6.1.123-1
6.1.128-1
6.12.12-1
6.12.13-1
Linux Kernel>=5.9<5.10.188
Linux Kernel>=5.11<5.15.123
Linux Kernel>=5.16<6.1.42
Linux Kernel>=6.2<6.4.7
Debian=12.0
Ubuntu=14.04
Ubuntu=16.04
Ubuntu=18.04
Ubuntu=20.04
Ubuntu=22.04

Remedy

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6eaf41e87a223ae6f8e7a28d6e78384ad7e407f8

Remedy

https://kernel.dance/6eaf41e87a223ae6f8e7a28d6e78384ad7e407f8

Remedy

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

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2023-3777?

    CVE-2023-3777 is classified as a high-severity vulnerability due to its potential for local privilege escalation.

  • How do I fix CVE-2023-3777?

    To mitigate CVE-2023-3777, update the kernel to a version higher than 6.5 or apply the latest patches provided by your distribution.

  • What systems are affected by CVE-2023-3777?

    CVE-2023-3777 affects multiple versions of the Linux kernel, specifically versions between 5.9 and 6.5, including various distributions such as Debian and Ubuntu.

  • Can CVE-2023-3777 be exploited remotely?

    CVE-2023-3777 is a local privilege escalation vulnerability and cannot be exploited remotely, requiring local access to the affected system.

  • What components of the Linux kernel does CVE-2023-3777 involve?

    CVE-2023-3777 involves a use-after-free vulnerability in the Linux kernel's netfilter component, specifically in the nf_tables functionality.

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