CVE-2021-3640: Canonical Ubuntu Linux

High severity, CVSS 7.0. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 20.04 only; version 21.10 only
• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 34 only
• Linux Linux Kernel: before 4.4.293 (fixed in 4.4.293); from 4.5, before 4.9.291 (fixed in 4.9.291); from 4.10, before 4.14.256 (fixed in 4.14.256); from 4.15, before 4.19.218 (fixed in 4.19.218); from 4.20, before 5.4.160 (fixed in 5.4.160); from 5.5.0, before 5.10.80 (fixed in 5.10.80); …
• Netapp h300e Firmware: affected versions not specified
• Netapp h300s Firmware: affected versions not specified
• Netapp h410c Firmware: affected versions not specified
• Netapp h410s Firmware: affected versions not specified
• Netapp h500e Firmware: affected versions not specified
• Netapp h500s Firmware: affected versions not specified
• Netapp h700e Firmware: affected versions not specified
• Netapp h700s Firmware: affected versions not specified

Published 2022-03-03. Last modified 2026-06-17.