From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-53072][MODERATE 7.0] Bluetooth: fix locking in hci_conn_request_evt() with HCI_PROTO_DEFER [ Upstream Date: Thu, 25 Jun 2026 16:24:13 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-53072 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 4 X-AL-KERNEL-Commit: 60e3f4ff02d1f2d55bfbf2ca32a97285a9771ee4 List-Id: CVE: CVE-2026-53072 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: Bluetooth: fix locking in hci_conn_request_evt() with HCI_PROTO_DEFER [ Upstream Commit: 60e3f4ff02d1f2d55bfbf2ca32a97285a9771ee4 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=60e3f4ff02d1f2d55bfbf2ca32a97285a9771ee4 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53072 Analysis date: Thu, 25 Jun 2026 16:24:13 -0400 ActionableScore: 5 ActionableScore lower bound: 4 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: A Bluetooth locking bug in `hci_conn_request_evt()` can call `hci_connect_cfm()` without `hdev->lock` in the `HCI_PROTO_DEFER` path, allowing an adjacent attacker in a specific SCO deferred-listen scenario to race connection deletion and trigger a kernel UAF, with realistic DoS impact and possible higher impact requiring manual review. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53072 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53072 The original announcement does not normally provide a security severity estimate, CVSS assessment, or enough information to determine whether the reported kernel bug represents a practically relevant security issue. This report was generated by AL-KERNEL, an AI-assisted Linux kernel vulnerability analysis system developed by Alexander Larkin. It combines an autonomous classifier with LLM-assisted technical analysis and a separate ActionableScore mechanism. The purpose of this report is to prioritize Linux kernel CVEs before manual review, identify cases that require prompt investigation, and support automatic closure of issues that are unlikely to have meaningful security impact. Published priority for this report: MODERATE 7.0 Manual review required: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-53072 MODERATE CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-416;CWE-362;CWE-667;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.5';DESCR 'Bluetooth hci_conn_request_evt can call hci_connect_cfm without hdev lock when HCI_PROTO_DEFER is set, while hci_connect_cfm normally assumes the device lock is held. If the connection object is deleted concurrently, this creates a race based use after free on conn and can crash the kernel. The reachable protocol context appears limited to deferred SCO listen handling because ISO does not generate HCI_EV_CONN_REQUEST. For the CVSS the PR:N is used in the paranoid score because an attacker only needs adjacent Bluetooth reachability to initiate the relevant connection request when the victim exposes the affected listening state. The issue is not Internet network reachable and requires Bluetooth radio proximity plus timing of the race. Impact is at least adjacent denial of service and in worst case may allow confidentiality or integrity impact due to kernel UAF, so manual review is recommended.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) MAYBE REMOTE LOCK UAF NETWORK KPANIC KPANIC DECREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCORELOWERTHAN7 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=4 ## 1. ActionableScore * Conservative score: 4 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum**:: ## 2. Signal breakdown * **Memory corruption, strong corruption primitive: +2** The commit explicitly describes a possible UAF when `hci_connect_cfm(conn)` is called without `hdev->lock` and `conn` is deleted concurrently. * **Real lifetime corruption: +1** This is a locking/lifetime bug around `struct hci_conn`, where the object may be freed while still being used. * **Reliable kernel crash / strong DoS: +1** A UAF dereference in the Bluetooth core can realistically crash the kernel. * **Weak LPE concern: +1** Kernel UAF bugs can sometimes be exploitable beyond DoS, but this patch does not show a controllable reclaim, arbitrary write, or clear object-confusion primitive. * **Hard or unreliable race / special timing required: -1** Triggering requires a concurrent deletion window while the deferred connection confirmation path is running. * **Adjacent external protocol influence: +1 in paranoid score** The event is externally influenced through Bluetooth radio proximity, but this is not Internet-reachable AV:N. It is closer to adjacent wireless reachability. ## 3. Reachability analysis The likely attacker is an adjacent Bluetooth attacker, not a remote Internet attacker. The victim must have Bluetooth enabled and expose the affected deferred SCO listening state. The commit notes that only SCO and ISO set `HCI_PROTO_DEFER`, and `HCI_EV_CONN_REQUEST` is not generated for ISO, so the practical path appears limited to SCO deferred setup listen handling. No local Linux user account is required in the adjacent attacker model. Namespaces and containers are not central to the trigger. Exploitation reliability is limited by the race window and by the need for a specific Bluetooth protocol state. ## 4. Severity interpretation This behaves above ordinary Moderate because it is a kernel UAF in a wireless protocol path with attacker-influenced events. It is not a clear Strong Important case from the patch alone because there is no demonstrated reclaim strategy, arbitrary write, controlled overwrite, or practical privilege-escalation chain. The realistic impact is adjacent DoS via kernel crash. The paranoid concern is that a kernel UAF may have confidentiality or integrity consequences after deeper manual analysis. ## 5. One-sentence report phrase A Bluetooth locking bug in `hci_conn_request_evt()` can call `hci_connect_cfm()` without `hdev->lock` in the `HCI_PROTO_DEFER` path, allowing an adjacent attacker in a specific SCO deferred-listen scenario to race connection deletion and trigger a kernel UAF, with realistic DoS impact and possible higher impact requiring manual review. ## 6. Manual review recommendation **MANUAL CHECK REQUIRED** Reason: this is a kernel UAF race in an externally influenced Bluetooth path. Even though the demonstrated impact is likely DoS and triggering is timing-dependent, the bug class is historically risky enough to avoid auto-closure. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: Bluetooth: fix locking in hci_conn_request_evt() with HCI_PROTO_DEFER [ Upstream Commit: 60e3f4ff02d1f2d55bfbf2ca32a97285a9771ee4 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=60e3f4ff02d1f2d55bfbf2ca32a97285a9771ee4 Changed files: net/bluetooth/hci_event.c Diff excerpt: Not included in this email. See the upstream URL for the full patch. Full patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=60e3f4ff02d1f2d55bfbf2ca32a97285a9771ee4 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53072 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53072 The original CVE announcement normally does not include a security-level estimate. In particular, it may not contain a CVSS assessment, an impact level, or enough information to determine whether the reported bug is a practically relevant security issue. One purpose of this parallel CVE list is to provide that missing technical and prioritization information. The original goal of the AL-KERNEL project was to prioritize Linux kernel CVE analysis automatically before manual review. The system can also help identify non-security issues that may be suitable for automatic closure. This report was generated by AL-KERNEL, an AI-assisted Linux kernel vulnerability analysis system developed by Alexander Larkin. The first analysis stage combines an autonomous classifier with additional LLM-based analysis. The autonomous classifier runs locally on a CPU and is based on a backpropagation neural network. Together, these mechanisms produce a technical vulnerability description, identify likely weakness types, estimate CVSS severity, and provide input for ActionableScore. Two CVSS estimates are retained because incomplete kernel vulnerability information often permits more than one defensible interpretation: Conservative CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 7.5 The conservative vector represents a lower-impact interpretation. The Best/paranoid vector intentionally represents a plausible upper-bound interpretation and should not automatically be treated as demonstrated real-world impact. CVSS may also need to be adjusted for a particular Linux deployment, because actual reachability, privileges, enabled kernel configuration, hardware, namespaces, exposed device nodes, and other environmental conditions can differ significantly between systems. A separate ActionableScore mechanism evaluates practical remediation urgency. Its analysis may include reachability, attack prerequisites, subsystem exposure, memory-corruption characteristics, denial-of-service reliability, and possible confidentiality, integrity, or privilege-escalation impact. Conservative ActionableScore: 4 Paranoid ActionableScore: 5 The final base severity is taken directly from the second tab-separated field of the AL-KERNEL classification result. ActionableScore does not replace or independently override that final AL-KERNEL decision, and if ActionableScore adjusted impact level of ALKERNEL, then you would see self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7. For an AL-KERNEL result of MODERATE, this report uses the following additional presentation split: ActionableScore below 5 -> MODERATE REGULAR ActionableScore 5 or more -> MODERATE 7.0 The distinction between MODERATE REGULAR and MODERATE 7.0 makes it possible to identify Moderate issues that should receive manual analysis and fixes before lower-priority MODERATE REGULAR issues. In many cases, MODERATE REGULAR fixes may wait for a later rebase or routine update. There is one override in which MODERATE REGULAR becomes MODERATE 7.0 even when the ActionableScore is below 5. When the AL-KERNEL result contains the KPANIC flag, a MODERATE result is always presented as MODERATE 7.0. The KPANIC flag selected with few regexps without usage of AI at all, so it helps to detect cases when Kernel Crash happens and similar (to filter False-Negative results from the LLM usage). KPANIC indicates that a reliable kernel crash, kernel panic, or similarly serious kernel availability impact was identified by the classification workflow. AL-KERNEL base severity for this report: MODERATE KPANIC detected for this report: YES Published priority for this report (same as in Subject): MODERATE 7.0 These results are intended to support engineering triage. They are machine-generated estimates, and cases marked for manual review should be validated by a human security engineer before final disposition. For more info read docs linked from here: https://kernelcve.org/ (and you can submit you own patch there to generate such a report for non-existant CVE-id yet). Note that in many cases this AI tool selects higher severity, than real is (means you can expect Importants instead of Moderate 7.0 or Moderates 7.0 instead of regular Moderates). If you see such cases, please use reply email interface to add additional manual analyses info to this particular CVE. And please, please, let me know when you see Lows instead of Importants or Important instead of Low (because particular for such cases I need to tune this AI tool to make it better for this one and next similar). My contact email for such notifications is alexanjelausa@gmail.com (and both send reply to CVE record itself too and see "reply" button below for howto reply).