Use-after-free in Linux kernel f2fs

1) Use-after-free

EUVDB-ID: #VU90129

Risk: Low

CVSSv3.1: 7.7 [AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-47335

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the init_f2fs_fs() and exit_f2fs_fs() functions in fs/f2fs/super.c, within the f2fs_recover_fsync_data() function in fs/f2fs/recovery.c, within the f2fs_destroy_garbage_collection_cache() function in fs/f2fs/f2fs.h. A local user can escalate privileges on the system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

External links

http://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048
http://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409
http://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a
http://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347

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.