What’s Vulnerable › Vulnerabilities

CVE-2021-3573

• Severity: medium (CVSS 6.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-08-13 · updated 2026-06-17
• Weakness: CWE-362

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.

Affected products

• Fedoraproject Fedora: 34
• Linux kernel: before 5.13; 5.13-rc1, 5.13-rc2, 5.13-rc3, 5.13-rc4 — fixed in 5.13
• Red Hat Enterprise Linux: 6.0, 7.0, 8.0

How to fix

Upgrade to a fixed version: Linux kernel 5.13. Check the vendor advisory for mitigations.

References

• http://www.openwall.com/lists/oss-security/2023/07/02/1
• https://bugzilla.redhat.com/show_bug.cgi?id=1966578
• https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/commit/?id=e305509e678b3a4af2b3cfd410f409f7cdaabb52
• https://www.openwall.com/lists/oss-security/2021/06/08/2
• http://www.openwall.com/lists/oss-security/2023/07/02/1
• https://bugzilla.redhat.com/show_bug.cgi?id=1966578
• https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/commit/?id=e305509e678b3a4af2b3cfd410f409f7cdaabb52
• https://www.openwall.com/lists/oss-security/2021/06/08/2

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