high
7.8
CWE
416
EPSS
0.042%
Advisory Published
Advisory Published
Updated

CVE-2023-3776: Use-after-free in Linux kernel's net/sched: cls_fw component

First published: Fri Jul 21 2023(Updated: )

A flaw in the Linux Kernel found. A use-after-free vulnerability in the Linux kernel's net/sched: cls_fw component can be exploited to achieve local privilege escalation. If tcf_change_indev() fails, fw_set_parms() will immediately return an error after incrementing or decrementing the reference counter in tcf_bind_filter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability. Reference: <a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=0323bce598eea038714f941ce2b22541c46d488f">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=0323bce598eea038714f941ce2b22541c46d488f</a>

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

Affected SoftwareAffected VersionHow to fix
redhat/Kernel<6.5
6.5
F5 Traffix Systems Signaling Delivery Controller=5.2.0=5.1.0
5.2.0
Linux Kernel>=2.6<6.5
Linux Kernel=6.5-rc1
Linux Kernel>=2.6.12<4.14.322
Linux Kernel>=4.15<4.19.291
Linux Kernel>=4.20<5.4.251
Linux Kernel>=5.5<5.10.188
Linux Kernel>=5.11<5.15.121
Linux Kernel>=5.16<6.1.40
Linux Kernel>=6.2<6.4.5
Debian GNU/Linux=10.0
Debian GNU/Linux=11.0
Debian GNU/Linux=12.0
debian/linux
5.10.223-1
5.10.226-1
6.1.123-1
6.1.119-1
6.12.11-1
6.12.12-1

Remedy

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=0323bce598eea038714f941ce2b22541c46d488f

Remedy

https://kernel.dance/0323bce598eea038714f941ce2b22541c46d488f

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-2023-3776?

    CVE-2023-3776 is considered a high-severity vulnerability due to its potential for local privilege escalation.

  • How do I fix CVE-2023-3776?

    To fix CVE-2023-3776, upgrade the Linux kernel to version 6.5 or apply the relevant patches provided by your distribution.

  • Which versions of the Linux kernel are affected by CVE-2023-3776?

    CVE-2023-3776 affects Linux kernel versions prior to 6.5, including multiple versions in the 4.x and 5.x series.

  • Can CVE-2023-3776 be exploited remotely?

    CVE-2023-3776 is a local privilege escalation vulnerability and cannot be exploited remotely.

  • What components of the Linux kernel are impacted by CVE-2023-3776?

    CVE-2023-3776 impacts the net/sched: cls_fw component of the Linux kernel.

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