CVE Catalog

CVE-2026-63944

HighCVSS 8.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.32%

25th percentile - higher than 25% of all known CVEs

Summary

In the Linux kernel Bluetooth subsystem, a use-after-free (UAF) vulnerability was found in hci_le_create_cis_sync. The conn pointer is dereferenced after releasing RCU and hci_dev_lock locks, allowing a concurrent disconnect to free memory before read. The cancellation mechanism in hci_conn_del() fails because queue and dequeue data mismatch.

Risk Assessment

An attacker could exploit this vulnerability for remote code execution or denial of service (DoS) by sending crafted Bluetooth packets, compromising system integrity and availability.

Recommendation

Immediately update the Linux kernel to a version containing the fix (commit 035c25007c9e or later). For embedded systems with Bluetooth, apply the security patch from your distributor.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing both rcu_read_lock() and hci_dev_lock(hdev). The conn pointer was obtained from an RCU-protected iteration over hdev->conn_hash.list and is not valid once these locks are dropped. A concurrent disconnect can free the hci_conn between the unlock and the dereference, causing a use-after-free read. The cancellation mechanism in hci_conn_del() cannot prevent this because hci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL: hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL); While hci_conn_del() dequeues with data=conn: hci_cmd_sync_dequeue(hdev, NULL, conn, NULL); Since NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never matches, and the pending work item is not cancelled. Fix this by saving conn->conn_timeout into a local variable while the locks are still held, so the stale conn pointer is never dereferenced after unlock. This is the same class of bug as the one fixed by commit 035c25007c9e ("Bluetooth: hci_sync: Fix UAF on le_read_features_complete") which addressed the identical pattern in a different function. This vulnerability was identified using 0sec.ai, an open-source automated security auditing platform (https://github.com/0sec-labs).

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