#VU83431 Use-after-free in Linux kernel - CVE-2020-25668

Vulnerability identifier: #VU83431

Vulnerability risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-25668

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

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

The vulnerability exists due to a use-after-free error within the con_font_op. A local authenticated user can trigger a use-after-free error and escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: before 4.4.242, 4.4.242

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External links
https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html
https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=90bfdeef83f1d6c696039b6a917190dcbbad3220
https://www.openwall.com/lists/oss-security/2020/10/30/1,
https://www.openwall.com/lists/oss-security/2020/11/04/3
https://bugzilla.redhat.com/show_bug.cgi?id=1893287,
https://www.openwall.com/lists/oss-security/2020/10/30/1
https://www.openwall.com/lists/oss-security/2020/11/04/3,
https://security.netapp.com/advisory/ntap-20210702-0005/

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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.