CVE-2026-74533: Bluetooth: ISO: fix race of kfree vs kref_get_unless_zero

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-15 · updated 2026-10-21

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix race of kfree vs kref_get_unless_zero hci_conn::iso_data is accessed and modified without lock or RCU. This leads to a race [Task hdev->workqueue] [Task 2] iso_recv iso_conn_put(conn) conn = LOAD hcon->iso_data iso_conn_free(conn) iso_conn_hold_unless_zero(conn) hcon->iso_data = NULL kfree(conn) kref_get_unless_zero(&conn->ref) /* UAF */ and also to races in iso_conn_add() vs. iso_conn_free(). Fix by adding spinlock hci_conn::proto_lock and using it to guard hci_conn::iso_data.

Affected products

Linux kernel: from 6.12.2 before 6.12.114; from 6.11.11 before 6.12; 6.13 — fixed in 6.12, 6.12.114, 7.2

How to fix

Upgrade to a fixed version: Linux kernel 6.12, 6.12.114, 7.2. Check the vendor advisory for mitigations.

References

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