Use-after-free in Linux kernel watchdog driver

1) Use-after-free

EUVDB-ID: #VU90101

Risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-47323

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 wdt_startup() function in drivers/watchdog/sc520_wdt.c. A local user can escalate privileges on the system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Linux kernel: 4.4 - 5.14 rc7

CPE2.3

• cpe:2.3:o:linux_foundation:linux_kernel:4.4:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.0:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.0-57:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.1:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.2:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.3:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.4:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.5:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.6:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:4.4.7:*:*:*:*:*:*:*

External links

https://git.kernel.org/stable/c/0015581a79bbf8e521f85dddb7d3e4a66b9f51d4
https://git.kernel.org/stable/c/b4565a8a2d6bffb05bfbec11399d261ec16fe373
https://git.kernel.org/stable/c/2aef07017fae21c3d8acea9656b10e3b9c0f1e04
https://git.kernel.org/stable/c/522e75ed63f67e815d4ec0deace67df22d9ce78e
https://git.kernel.org/stable/c/7c56c5508dc20a6b133bc669fc34327a6711c24c
https://git.kernel.org/stable/c/a173e3b62cf6dd3c4a0a10c8a82eedfcae81a566
https://git.kernel.org/stable/c/b3c41ea5bc34d8c7b19e230d80e0e555c6f5057d
https://git.kernel.org/stable/c/f0feab82f6a0323f54d85e8b512a2be64f83648a
https://git.kernel.org/stable/c/90b7c141132244e8e49a34a4c1e445cce33e07f4
https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.240
https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.198
https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.4.276
https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.276
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.52
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.19
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.134

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.