Use-after-free in Linux kernel en rep driver

1) Use-after-free

EUVDB-ID: #VU90090

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-2021-47247

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 mlx5e_take_all_route_decap_flows() and mlx5e_encap_valid() functions in drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c, within the wait_for_completion() and mlx5e_take_all_encap_flows() functions in drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c, within the mlx5e_rep_neigh_update() and mlx5e_rep_update_flows() functions in drivers/net/ethernet/mellanox/mlx5/core/en/rep/neigh.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/b6447b72aca571632e71bb73a797118d5ce46a93
http://git.kernel.org/stable/c/fb1a3132ee1ac968316e45d21a48703a6db0b6c3

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.