Use-after-free in Linux kernel x86 net

1) Use-after-free

EUVDB-ID: #VU90100

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-2021-47303

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 jit_subprogs() function in kernel/bpf/verifier.c, within the bpf_prog_free_deferred() function in kernel/bpf/core.c, within the bpf_tail_call_direct_fixup() function in arch/x86/net/bpf_jit_comp.c. 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/a9f36bf3613c65cb587c70fac655c775d911409b
http://git.kernel.org/stable/c/599148d40366bd5d1d504a3a8fcd65e21107e500
http://git.kernel.org/stable/c/f263a81451c12da5a342d90572e317e611846f2c

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.