CVE-2021-3640
kernel: use-after-free vulnerability in function sco_sock_sendmsg()
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · July 18, 2021
Updated · June 28, 2026
Description
A flaw use-after-free in function sco_sock_sendmsg() of the Linux kernel HCI subsystem was found in the way user calls ioct UFFDIO_REGISTER or other way triggers race condition of the call sco_conn_del() together with the call sco_sock_sendmsg() with the expected controllable faulting memory page. A privileged local user could use this flaw to crash the system or escalate their privileges on the system.
Statement
This issue is rated as having a Moderate impact because of the privileges (CAP_NET_ADMIN in initial namespace) required for exploiting the issue.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVSS / CWE
CVSS 3.1 · 6.7CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CWE-825 · Expired Pointer Dereference