high
7.8
CWE
416
Advisory Published
Updated

CVE-2023-3609: Use-after-free in Linux kernel's net/sched: cls_u32 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_u32 component can be exploited to achieve local privilege escalation. If tcf_change_indev() fails, u32_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=04c55383fa5689357bcdd2c8036725a55ed632bc">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=04c55383fa5689357bcdd2c8036725a55ed632bc</a>

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

Affected SoftwareAffected VersionHow to fix
redhat/Kernel<6.4
6.4
Linux Kernel>=4.14<6.4
Linux Kernel=6.4-rc1
Linux Kernel=6.4-rc2
Linux Kernel=6.4-rc3
Linux Kernel=6.4-rc4
Linux Kernel=6.4-rc5
Linux Kernel=6.4-rc6
Debian GNU/Linux=10.0
Debian GNU/Linux=11.0
debian/linux
5.10.223-1
5.10.226-1
6.1.123-1
6.1.128-1
6.12.12-1
6.12.15-1
Debian=10.0
Debian=11.0
IBM Security Verify Governance - Identity Manager<=ISVG 10.0.2
IBM Security Verify Governance, Identity Manager<=ISVG 10.0.2

Remedy

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=04c55383fa5689357bcdd2c8036725a55ed632bc

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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Parent vulnerabilities

(Appears in the following advisories)

Frequently Asked Questions

  • What is the severity of CVE-2023-3609?

    CVE-2023-3609 is classified as a high severity vulnerability due to its potential for local privilege escalation.

  • How do I fix CVE-2023-3609?

    To address CVE-2023-3609, upgrade the Linux kernel to version 6.4 or apply the recommended patches.

  • Which Linux versions are affected by CVE-2023-3609?

    CVE-2023-3609 affects Linux kernel versions from 4.14 up to but not including 6.4.

  • What components are impacted by CVE-2023-3609?

    CVE-2023-3609 affects the cls_u32 component of the Linux kernel's networking subsystem.

  • Is CVE-2023-3609 exploitable remotely?

    CVE-2023-3609 is not known to be exploitable remotely, as it requires local access to achieve privilege escalation.

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