Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63944
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:12 UTC
Updated2026-07-20 15:16:58 UTC
DescriptionIn 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).

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.002000000 probability, percentile 0.100190000 (date 2026-07-20)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.8HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected c09b80be6ffc338634b2f5f8cfa12b6843410834 a55618c0f4cead9e59c63f5ee030d393fd70d861 git Not specified
CNA Linux Linux affected c09b80be6ffc338634b2f5f8cfa12b6843410834 a921957d39290143629eb38c4f74b9bef8035d0a git Not specified
CNA Linux Linux affected c09b80be6ffc338634b2f5f8cfa12b6843410834 d9019210c8c30d40eb20094274cc647e352f48f7 git Not specified
CNA Linux Linux affected c09b80be6ffc338634b2f5f8cfa12b6843410834 380e67b1794a9a281a0cb592b4e62077fbd0c8ca git Not specified
CNA Linux Linux affected c09b80be6ffc338634b2f5f8cfa12b6843410834 bfea6091e0fffb270c20e74384b660910277eb6c git Not specified
CNA Linux Linux affected 6.4 Not specified
CNA Linux Linux unaffected 6.4 semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.93 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.35 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.12 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/380e67b1794a9a281a0cb592b4e62077fbd0c8ca 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a921957d39290143629eb38c4f74b9bef8035d0a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a55618c0f4cead9e59c63f5ee030d393fd70d861 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bfea6091e0fffb270c20e74384b660910277eb6c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d9019210c8c30d40eb20094274cc647e352f48f7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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