NULL pointer dereference in Linux kernel nfsd

1) NULL pointer dereference

EUVDB-ID: #VU90389

Risk: Low

CVSSv3.1: 4.8 [AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-47507

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to NULL pointer dereference within the init_nfsd(), nfsd4_exit_pnfs() and exit_nfsd() functions in fs/nfsd/nfsctl.c, within the register_cld_notifier() function in fs/nfsd/nfs4recover.c. A local user can perform a denial of service (DoS) attack.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

CPE2.3

External links

http://git.kernel.org/stable/c/f5734b1714ca355703e9ea8fb61d04beff1790b9
http://git.kernel.org/stable/c/c520943a00ad5015704969ad3304c956bcd49d25
http://git.kernel.org/stable/c/8bf902fee5893cfc2f04a698abab47629699ae9a
http://git.kernel.org/stable/c/b10252c7ae9c9d7c90552f88b544a44ee773af64

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.