CVE-2026-74535: Bluetooth: ISO: avoid deadlocks in iso_sock_timeout

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 2026-10-16

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: avoid deadlocks in iso_sock_timeout iso_sock_timeout() takes lock_sock, so sync disabling the timer while holding that lock may deadlock. iso_sock_timeout() may also run concurrently with iso_conn_del(), which leads to UAF [Task 1] [Task hdev->workqueue] iso_sock_timeout iso_conn_del iso_conn_hold_unless_zero iso_chan_del `------------> iso_conn_put caller frees hcon iso_conn_put iso_conn_free conn->hcon->iso_data = NULL; /* UAF */ Fix the deadlock by removing the disable from the lock_sock sections. Move the timer from iso_conn to iso_pinfo to decouple it from iso_conn which may need to be freed in lock_sock section. Convert some of the clear_timer to disable_timer.

Affected products

Linux kernel: from 6.12.2 before 6.12.103; from 6.11.11 before 6.12; 6.13 — fixed in 6.12, 6.12.103, 7.2

How to fix

Upgrade to a fixed version: Linux kernel 6.12, 6.12.103, 7.2. Check the vendor advisory for mitigations.

References

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