CVE-2021-3573

Name: CVE-2021-3573
Creator: NVD / NIST
Published: 2021-08-13T14:15:07.617+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.4/10EPSS 0.37%

Last modified Jun 17, 2026

CVE-2021-3573 is a medium-severity vulnerability rated 6.4/10 on the CVSS scale. A use-after-free in function hci_sock_bound_ioctl() of the Linux kernel HCI subsystem was found in the way user calls ioct HCIUNBLOCKADDR or other way triggers race condition of the call hci_unregister_dev() together with one of the calls hci_sock_blacklist_add(), hci_sock_blacklist_del(), hci_get_conn_info(), hci_get_auth_info(). A privileged local user could use this flaw to crash the system or escalate their privileges on the system. EPSS estimates a 0.37% chance of exploitation in the next 30 days.

Description

A use-after-free in function hci_sock_bound_ioctl() of the Linux kernel HCI subsystem was found in the way user calls ioct HCIUNBLOCKADDR or other way triggers race condition of the call hci_unregister_dev() together with one of the calls hci_sock_blacklist_add(), hci_sock_blacklist_del(), hci_get_conn_info(), hci_get_auth_info(). A privileged local user could use this flaw to crash the system or escalate their privileges on the system. This flaw affects the Linux kernel versions prior to 5.13-rc5.

Metrics

CVSS 3.1

6.4/10

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.37%

28.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-362

Affected Software

Vendor	Product	Versions	Update
Linux	Linux Kernel	< 5.13	—
Linux	Linux Kernel	5.13	Rc1
Redhat	Enterprise Linux	6.0	—
Redhat	Enterprise Linux	7.0	—
Redhat	Enterprise Linux	8.0	—
Fedoraproject	Fedora	34	—

References

http://www.openwall.com/lists/oss-security/2023/07/02/1
https://bugzilla.redhat.com/show_bug.cgi?id=1966578Issue Tracking, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/commit/?id=e305509e678b3a4af2b3cfd410f409f7cdaabb52Patch, Vendor Advisory
https://www.openwall.com/lists/oss-security/2021/06/08/2Exploit, Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2023/07/02/1
https://bugzilla.redhat.com/show_bug.cgi?id=1966578Issue Tracking, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/commit/?id=e305509e678b3a4af2b3cfd410f409f7cdaabb52Patch, Vendor Advisory
https://www.openwall.com/lists/oss-security/2021/06/08/2Exploit, Mailing List, Third Party Advisory

Timeline

Published: Aug 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3573?

How severe is CVE-2021-3573?

CVE-2021-3573 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3573?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3573?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST