#VU63767 Use-after-free in Linux kernel - CVE-2021-3752

Vulnerability identifier: #VU63767

Vulnerability risk: Low

CVSSv4.0: 4.8 [CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3752

CWE-ID: CWE-416

Exploitation vector: Local network

Exploit availability: No

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

Vendor: Linux Foundation

Description

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to a use-after-free error in the Linux kernel’s Bluetooth subsystem when a user calls connect to the socket and disconnect simultaneously. A local user can escalate privileges on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.15.3, 5.15.3

---

External links
https://lore.kernel.org/lkml/20211115165435.133245729@linuxfoundation.org/
https://www.openwall.com/lists/oss-security/2021/09/15/4
https://bugzilla.redhat.com/show_bug.cgi?id=1999544
https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
https://www.debian.org/security/2022/dsa-5096
https://security.netapp.com/advisory/ntap-20220318-0009/

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.