Linux Kernel up to 7.1.7/7.2-rc5 Bluetooth ISO iso_conn_add/iso_conn_free use after free

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.7/7.2-rc5. It has been rated as very critical. This issue affects the function iso_conn_add/iso_conn_free of the component Bluetooth ISO. The manipulation leads to use after free. This vulnerability is referenced as CVE-2026-74533. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 7.1.7/7.2-rc5. This issue affects the function iso_conn_add/iso_conn_free of the component Bluetooth ISO. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-74533 since 08/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 7.1.8 or 7.2-rc6 eliminates this vulnerability. Applying the patch 876a3e94c70d0859d1dad1c986112d4f0d99eba8/af24e338bf5dafb80f42baa9a0b9e9b57b1c5d9c is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.1.6
• 7.1.7
• 7.2-rc1
• 7.2-rc2
• 7.2-rc3
• 7.2-rc4
• 7.2-rc5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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