CVE-2026-74533

HighCVSS 8.8

Published: 15/08/2026(UTC)Updated: 17/08/2026(UTC)Translated: 15/08/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.22%

13th percentile - higher than 13% of all known CVEs

Summary

In the Linux kernel, in the Bluetooth ISO subsystem, a race condition was found between kfree and kref_get_unless_zero on the hci_conn::iso_data field, which is accessed and modified without synchronization (lock or RCU). This can lead to use-after-free (UAF) and races between iso_conn_add() and iso_conn_free().

Risk Assessment

Use-after-free can lead to system crashes or security breaches, including arbitrary code execution by an attacker.

Recommendation

Apply the kernel patch that adds a spinlock hci_conn::proto_lock to guard hci_conn::iso_data. Update the system to a kernel version with the fix.

Original NVD description (English source)

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.