CVE-2026-90093: Bluetooth: L2CAP: access chan->conn safely in get/setsockopt

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: access chan->conn safely in get/setsockopt Since commit b66774b48dd9 ("Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref") l2cap_chan::conn has held reference and remains non-NULL also after the corresponding hci_conn is deleted. In this state accessing various fields eg. hci_conn::hdev is invalid, which leads to KASAN crash in l2cap_sock_setsockopt() access of conn->hcon->hdev. Check l2cap_chan::conn.hcon corresponds to an alive hci_conn before trying to use it in l2cap_sock.c. Hold l2cap_chan_lock() in getsockopt/setsockopt to ensure it stays alive, and to avoid data races in l2cap_chan fields.

Affected products

Linux: from 5.10.265 before 5.10.273; from 5.15.216 before 5.15.224; from 6.1.183 before 6.1.191; from 6.6.145 before 6.6.160; from 6.12.97 before 6.12.114; from 6.18.39 before 6.18.57 — fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.114, 6.18.57

How to fix

Upgrade to a fixed version: Linux 5.10.273, 5.15.224, 6.1.191, 6.6.160. Check the vendor advisory for mitigations.

References

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