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Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user After commit ab4eedb790ca ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del"), l2cap_conn_del() uses conn->lock to protect access to conn->users. However, l2cap_register_user() and l2cap_unregister_user() don't use conn->lock, creating a race condition where these functions can access conn->users and conn->hchan concurrently with l2cap_conn_del(). This can lead to use-after-free and list corruption bugs, as reported by syzbot. Fix this by changing l2cap_register_user() and l2cap_unregister_user() to use conn->lock instead of hci_dev_lock(), ensuring consistent locking for the l2cap_conn structure.

Products
Kernel
Affected versions
Not specified
Fixed versions
6.12.78, 6.18.20, 6.19.10, 6.6.130
CVEs
CVE-2026-23461
Confirmed fixed CVEs
Not specified
Updated in this feed
8 Nov 2026, 02:48 UTC · Revision 1

Source evidence

Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user

core-osv · Original source

Published 3 Apr 2026, 15:15 UTC

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user After commit ab4eedb790ca ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del"), l2cap_conn_del() uses conn->lock to protect access to conn->users. However, l2cap_register_user() and l2cap_unregister_user() don't use conn->lock, creating a race condition where these functions can access conn->users and conn->hchan concurrently with l2cap_conn_del(). This can lead to use-after-free and list corruption bugs, as reported by syzbot. Fix this by changing l2cap_register_user() and l2cap_unregister_user() to use conn->lock instead of hci_dev_lock(), ensuring consistent locking for the l2cap_conn structure.

osv:CVE-2026-23461

Kernel

Fixed versions: 6.6.130, 6.12.78, 6.18.20, 6.19.10

Complete source record
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