#VU20917 Use-after-free in Linux kernel - CVE-2018-20976

Vulnerability identifier: #VU20917

Vulnerability 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-2018-20976

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 user to compromise vulnerable system.

The vulnerability exists in "fs/xfs/xfs_super.c" due to a use-after-free error when the "xfs_fs_fill_super" fails. A local authenticated user can execute arbitrary code on the target system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: 4.0 - 4.0.9, 4.1 - 4.17.19, 4.2 - 4.2.8, 4.3 - 4.3.6, 4.4 - 4.4.191, 4.5 - 4.5.7, 4.6 rc1 - 4.6.7, 4.7 - 4.7.10, 4.8 - 4.8.17, 4.9 - 4.9.191

---

External links
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c9fbd7bbc23dbdd73364be4d045e5d3612cf6e82

---

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.