#VU90901 Double free in Linux kernel - CVE-2021-46938

Vulnerability identifier: #VU90901

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-46938

CWE-ID: CWE-415

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local user to execute arbitrary code.

The vulnerability exists due to a double free error within the blk_mq_free_tag_set() and dm_mq_cleanup_mapped_device() functions in drivers/md/dm-rq.c. A local user can execute arbitrary code.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

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External links
https://git.kernel.org/stable/c/8ae0185255eaf05bd66f4215c81e99bf01140fd9
https://git.kernel.org/stable/c/b42c0a33dfdd451d9be62dd5de58c39f2750b6e3
https://git.kernel.org/stable/c/772b9f59657665af3b68d24d12b9d172d31f0dfb
https://git.kernel.org/stable/c/a992a283c0b77d0a7c2c348add0e6a21fb1dab67
https://git.kernel.org/stable/c/1cb02dc76f4c0a2749a02b26469512d6984252e9
https://git.kernel.org/stable/c/6086f957416a6e87236c06079fcaba7a3998aeca
https://git.kernel.org/stable/c/d757bf4c69cda3c3ab7f775dfabbf5a80e2f6f9d
https://git.kernel.org/stable/c/8e947c8f4a5620df77e43c9c75310dc510250166

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.