CVE-2026-74535

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

0.24%

16th percentile - higher than 16% of all known CVEs

Summary

In the Linux kernel, in the Bluetooth ISO subsystem, a potential deadlock was found in iso_sock_timeout(), which takes lock_sock and then synchronously disables the timer, potentially causing a deadlock. Additionally, iso_sock_timeout() may run concurrently with iso_conn_del(), leading to use-after-free (UAF) — one thread frees the hcon structure while another tries to access it.

Risk Assessment

Deadlock can cause system hang or crash, and use-after-free can lead to security breaches, including arbitrary code execution by an attacker.

Recommendation

Apply the kernel patch that removes timer disabling from lock_sock sections and moves the timer to iso_pinfo to decouple it from iso_conn. 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: 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.