#VU93603 Race condition in Linux kernel - CVE-2021-47461

Vulnerability identifier: #VU93603

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-2021-47461

CWE-ID: CWE-362

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 escalate privileges on the system.

The vulnerability exists due to a race condition within the userfaultfd_writeprotect() function in fs/userfaultfd.c. A local user can escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

---

External links
https://git.kernel.org/stable/c/3cda4bfffd4f755645577aaa9e96a606657b4525
https://git.kernel.org/stable/c/149958ecd0627a9f1e9c678c25c665400054cd6a
https://git.kernel.org/stable/c/cb185d5f1ebf900f4ae3bf84cee212e6dd035aca

---

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.