Privilege escalation in Linux kernel on NUMA systems

1) Use-after-free

EUVDB-ID: #VU55260

Risk: Low

CVSSv4.0: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2019-20934

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 in Linux fair scheduler within the show_numa_stats() function, caused by improperly freed NUMA fault statistics. A local user can trigger a use-after-free error and escalate privileges on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.2.6

CPE2.3

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

External links

https://bugs.chromium.org/p/project-zero/issues/detail?id=1913
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.2.6
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=16d51a590a8ce3befb1308e0e7ab77f3b661af33

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.