Linux Kernel up to 5.10.34/5.11.18/5.12.1 qrtr ul_callback use after free

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 5.10.34/5.11.18/5.12.1. This issue affects the function ul_callback of the component qrtr. The manipulation leads to use after free. This vulnerability is documented as CVE-2021-46973. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.10.34/5.11.18/5.12.1 (Operating System). It has been rated as critical. This issue affects the function ul_callback of the component qrtr. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: Avoid potential use after free in MHI send It is possible that the MHI ul_callback will be invoked immediately following the queueing of the skb for transmission, leading to the callback decrementing the refcount of the associated sk and freeing the skb. As such the dereference of skb and the increment of the sk refcount must happen before the skb is queued, to avoid the skb to be used after free and potentially the sk to drop its last refcount..

The weakness was released 02/27/2024. It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2021-46973. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/14/2025).

Upgrading to version 5.10.35, 5.11.19, 5.12.2 or 5.13 eliminates this vulnerability. Applying the patch 48ec949ac979/ea474054c2cc/03c649dee8b1/47a017f33943 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.0
• 5.10.1
• 5.10.2
• 5.10.3
• 5.10.4
• 5.10.5
• 5.10.6
• 5.10.7
• 5.10.8
• 5.10.9
• 5.10.10
• 5.10.11
• 5.10.12
• 5.10.13
• 5.10.14
• 5.10.15
• 5.10.16
• 5.10.17
• 5.10.18
• 5.10.19
• 5.10.20
• 5.10.21
• 5.10.22
• 5.10.23
• 5.10.24
• 5.10.25
• 5.10.26
• 5.10.27
• 5.10.28
• 5.10.29
• 5.10.30
• 5.10.31
• 5.10.32
• 5.10.33
• 5.10.34
• 5.11.0
• 5.11.1
• 5.11.2
• 5.11.3
• 5.11.4
• 5.11.5
• 5.11.6
• 5.11.7
• 5.11.8
• 5.11.9
• 5.11.10
• 5.11.11
• 5.11.12
• 5.11.13
• 5.11.14
• 5.11.15
• 5.11.16
• 5.11.17
• 5.11.18
• 5.12.0
• 5.12.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

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