Linux Kernel up to 5.18.7 del_gendisk use after free

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 5.18.7. Affected by this vulnerability is the function del_gendisk. The manipulation leads to use after free. This vulnerability is referenced as CVE-2022-49694. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.18.7 and classified as critical. This issue affects the function del_gendisk. 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: block: disable the elevator int del_gendisk The elevator is only used for file system requests, which are stopped in del_gendisk. Move disabling the elevator and freeing the scheduler tags to the end of del_gendisk instead of doing that work in disk_release and blk_cleanup_queue to avoid a use after free on q->tag_set from disk_release as the tag_set might not be alive at that point. Move the blk_qos_exit call as well, as it just depends on the elevator exit and would be the only reason to keep the not exactly cheap queue freeze in disk_release.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2022-49694 since 02/26/2025. The exploitation is known to be easy. 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 03/06/2025).

Upgrading to version 5.18.8 eliminates this vulnerability. Applying the patch f28699fafc047ec33299da01e928c3a0073c5cc6/50e34d78815e474d410f342fbe783b18192ca518 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

• 5.18.0
• 5.18.1
• 5.18.2
• 5.18.3
• 5.18.4
• 5.18.5
• 5.18.6
• 5.18.7

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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