CVE-2026-74533 is a vulnerability in Linux Kernel
Published on August 15, 2026
Bluetooth: ISO: fix race of kfree vs kref_get_unless_zero
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.
Products Associated with CVE-2026-74533
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Affected Versions
Linux:- Version dc26097bdb864a0d5955b9a25e43376ffc1af99b and below 876a3e94c70d0859d1dad1c986112d4f0d99eba8 is affected.
- Version dc26097bdb864a0d5955b9a25e43376ffc1af99b and below af24e338bf5dafb80f42baa9a0b9e9b57b1c5d9c is affected.
- Version f53e7489273dc2bb307bf50f319b3762d45534f0 is affected.
- Version a58d0f5dac322e16cc75334d000666512341bde5 is affected.
- Version 6.11.11 and below 6.12 is affected.
- Version 6.12.2 and below 6.13 is affected.
- Version 6.13 is affected.
- Before 6.13 is unaffected.
- Version 7.1.8, <= 7.1.* is unaffected.
- Version 7.2-rc6, <= * is unaffected.