out-of-bounds write in qfq_change_class function
CVE: CVE-2023-31436
Component: kernel
CWE: CWE-787
Severity: Important
CVSS v3: 7.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Release date: 2023-04-13T00:00:00+00:00

An out-of-bounds memory access flaw was found in the Linux kernel’s traffic control (QoS) subsystem in how a user triggers the qfq_change_class function with an incorrect MTU value of the network device used as lmax. This flaw allows a local user to crash or potentially escalate their privileges on the system.


Remediation:
Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
To mitigate this issue, prevent the module, sch_qfq from being loaded. Please see https://access.redhat.com/solutions/41278 for information on how to blacklist a kernel module to prevent it from loading automatically.