CVE Catalog

CVE-2026-23461

HighCVSS 8.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.25%

16th percentile - higher than 16% of all known CVEs

Summary

In the Linux kernel, the Bluetooth L2CAP subsystem has a use-after-free vulnerability in l2cap_unregister_user. Missing locking (conn->lock) between l2cap_conn_del() and registration functions causes a race condition leading to use-after-free and list corruption.

Risk Assessment

An attacker could exploit this to crash the system or potentially escalate privileges via kernel memory corruption.

Recommendation

Update the Linux kernel to a version containing the fix (commit referenced in the description).

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS