Use after free in Linux kernel

1) Use after free

EUVDB-ID: #VU92762

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-2020-25669

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a local user to execute arbitrary code.

A vulnerability was found in the Linux Kernel where the function sunkbd_reinit having been scheduled by sunkbd_interrupt before sunkbd being freed. Though the dangling pointer is set to NULL in sunkbd_disconnect, there is still an alias in sunkbd_reinit causing Use After Free.

Mitigation

Install update from vendor's repository.

Vulnerable software versions

Linux kernel: All versions

CPE2.3

• cpe:2.3:o:linux_foundation:linux_kernel:*:*:*:*:*:*:*:*

External links

https://github.com/torvalds/linux/commit/77e70d351db7de07a46ac49b87a6c3c7a60fca7e
https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html
https://www.openwall.com/lists/oss-security/2020/11/20/5
https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html
https://www.openwall.com/lists/oss-security/2020/11/05/2
https://www.openwall.com/lists/oss-security/2020/11/05/2,
https://www.openwall.com/lists/oss-security/2020/11/20/5,
https://security.netapp.com/advisory/ntap-20210702-0006/

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.