#VU90666 NULL pointer dereference in Linux kernel - CVE-2021-3739

Vulnerability identifier: #VU90666

Vulnerability risk: Low

CVSSv4.0: 4.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3739

CWE-ID: CWE-476

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 read data or crash the application.

The vulnerability exists due to NULL pointer dereference within the btrfs_rm_device() function in fs/btrfs/volumes.c. A local user can read data or crash the application.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

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External links
https://ubuntu.com/security/CVE-2021-3739
https://www.openwall.com/lists/oss-security/2021/08/25/3
https://bugzilla.redhat.com/show_bug.cgi?id=1997958
https://github.com/torvalds/linux/commit/e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
https://security.netapp.com/advisory/ntap-20220407-0006/

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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.