Privilege escalation in Linux kernel VM_PFNMAP VMA

1) Race condition

EUVDB-ID: #VU67478

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-39188

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

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

The vulnerability exists due to a race condition within include/asm-generic/tlb.h in the Linux kernel. A local user can exploit the race and escalate privileges on the system.

Note, this only occurs in situations with VM_PFNMAP VMAs.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.19

External links

http://github.com/torvalds/linux/commit/b67fbebd4cf980aecbcc750e1462128bffe8ae15
http://lore.kernel.org/stable/CAG48ez3SEqOPcPCYGHVZv4iqEApujD5VtM3Re-tCKLDEFdEdbg@mail.gmail.com/
http://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.19
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b67fbebd4cf980aecbcc750e1462128bffe8ae15
http://bugs.chromium.org/p/project-zero/issues/detail?id=2329

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.