Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind
CVE-2026-90256 · published 17 Sept 2026
How serious is it
- Severity: high, CVSS score 8.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-90256?
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Who is affected
- Linux Linux: efc30877bd4bc85fefe98d80af60fafc86e5775e to < 0fa448369c87e20b2aeaeaca0187d698dd61f791, f87271d21dd4ee83857ca11b94e7b4952749bbae to < 7c032b6d48a46634cbd58aaebad2638c00ad3b51, ab4eedb790cae44313759b50fe47da285e2519d5 to < b495a3a9b33bc4e4613e685bf5c96c136caa22d8, ab4eedb790cae44313759b50fe47da285e2519d5 to < 2b66c83ff1751d6bd3201b3017206262ab46dc05
- Linux Linux: 6.14
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/0fa448369c87e20b2aeaeaca0187d698dd61f791
- git.kernel.org/stable/c/7c032b6d48a46634cbd58aaebad2638c00ad3b51
- git.kernel.org/stable/c/b495a3a9b33bc4e4613e685bf5c96c136caa22d8
- git.kernel.org/stable/c/2b66c83ff1751d6bd3201b3017206262ab46dc05
Merged from CVE List. Last updated 26 Oct 2026. All vulnerabilities · RSS · JSON