#VU68300 Improper Privilege Management in Linux kernel - CVE-2021-41073

Vulnerability identifier: #VU68300

Vulnerability risk: Low

CVSSv4.0: 7.1 [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:P/U:Clear]

CVE-ID: CVE-2021-41073

CWE-ID: CWE-269

Exploitation vector: Local

Exploit availability: Yes

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

Vendor: Linux Foundation

Description

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to improper privilege management within the loop_rw_iter() function in fs/io_uring.c in Linux kernel. A local user can escalate privileges on the system by using IORING_OP_PROVIDE_BUFFERS to trigger a free of a kernel buffer.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: All versions

---

External links
https://www.openwall.com/lists/oss-security/2021/09/18/2
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=16c8d2df7ec0eed31b7d3b61cb13206a7fb930cc
https://www.debian.org/security/2021/dsa-4978
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PAP4TXEZ7J4EZQMQW5SIJMWXG7WZT3F7/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/J7KSMIOQ4377CVTHMWNGNCWHMCRFRP2T/
https://security.netapp.com/advisory/ntap-20211014-0003/
https://www.openwall.com/lists/oss-security/2022/06/04/4

---

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. However, proof of concept for this vulnerability is available.