From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68390][MODERATE 7.0] Bluetooth: hci_sync: hold hdev->lock for hci_conn_params lookups [ Upstream Date: Mon, 10 Aug 2026 11:13:43 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68390 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: 8d892bec1dd134761cabec6ba23fe315d0f20f98 List-Id: CVE: CVE-2026-68390 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: Bluetooth: hci_sync: hold hdev->lock for hci_conn_params lookups [ Upstream Commit: 8d892bec1dd134761cabec6ba23fe315d0f20f98 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8d892bec1dd134761cabec6ba23fe315d0f20f98 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68390 Analysis date: Mon, 10 Aug 2026 11:13:43 -0400 ActionableScore: 5 ActionableScore lower bound: 4 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: Unlocked Bluetooth hci_sync lookups can race with connection parameter updates or teardown, creating a plausible stale pointer or UAF condition that can crash the kernel and warrants manual review despite no demonstrated privilege escalation primitive. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68390 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68390 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-2026-68390 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';CWE-362;CWE-667;*CWE-416;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'Bluetooth hci_sync performed hci_conn_params_lookup and related hci_conn access without holding hdev lock, even though the lookup requires that lock for safe list traversal and parameter access. This creates a race with concurrent Bluetooth connection parameter updates or connection teardown and can lead to stale pointer use, use-after-free, or a kernel crash. For the CVSS the PR:L because reliable triggering normally requires a local process able to exercise Bluetooth LE connection or synchronization control paths, but it does not necessarily require full administrative control in all deployments. The issue is not directly reachable over IP networking. A nearby Bluetooth device may help shape timing or connection state, but the vulnerable operation is primarily in the local Bluetooth control path. Impact is at least local denial of service via kernel crash and in the paranoid case may allow confidentiality or integrity impact due to a plausible UAF race.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) SKIP CVE-2026-68390 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: c530569adc19b5f0c62955de41f067bad34e3fe0 YES NO NO unknown MAYBE REMOTE SIMPLEFIX NETWORK KPANIC - - 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 * Local unprivileged trigger: +1. A local user or local process may be able to exercise Bluetooth LE connection or synchronization paths through normal Bluetooth user workflows, depending on policy and bluetoothd exposure. * Memory corruption, weak/indirect corruption candidate: +1. The patch fixes unlocked list and parameter access in hci_conn_params_lookup and related hci_conn handling, which is a plausible stale pointer or unsafe traversal case. * Real lifetime corruption: +1. The change copies le->handle while hdev->lock is held and avoids passing an unlocked hci_conn pointer later, indicating a real object lifetime or concurrent teardown concern. * Reliable kernel crash / strong DoS: +1. Unsafe list traversal or stale object access in kernel Bluetooth state can realistically crash the kernel. * Broad/default/common subsystem: +1. Bluetooth is a common kernel subsystem on laptops, desktops, mobile, and embedded systems when enabled. * Hard or unreliable race / special timing required: -1. The issue depends on concurrent lookup and parameter update or connection teardown timing. * Paranoid only, firmware-mediated or nearby-device-influenced external state: +1. A Bluetooth controller or nearby peer may help shape connection timing and state, but this is not equivalent to ordinary IP network reachability. Race-UAF cap applied: conservative score capped at 4 and paranoid score capped at 5 because the patch suggests a race/lifetime bug but does not show attacker-controlled reclaim, write-after-free, callback control, type confusion, or refcount takeover. Call-site confidence: high. The affected call sites and the changed pointer-to-handle lifetime mitigation are present in the patch. ## 3. Reachability analysis A local process that can trigger Bluetooth LE connection creation or periodic advertising synchronization paths is the most realistic trigger. In typical desktop deployments this may be exposed indirectly through bluetoothd and session policy, so PR:L is more appropriate than PR:H for practical triage. This is not directly reachable over IP networking. A nearby Bluetooth device may influence connection state or timing, but the vulnerable operation is mainly in the local Bluetooth control path. Containers usually do not get direct access to the host Bluetooth controller unless explicitly delegated, so container reachability depends on device and D-Bus policy. The path also requires Bluetooth support to be enabled and the relevant LE or PAST-related workflows to be used. ## 4. Severity interpretation This behaves like an actionable Moderate issue rather than an ordinary low-priority Moderate. The realistic impact is local kernel crash or system instability from a race in Bluetooth connection state handling. The theoretical concern is UAF or stale pointer use because required locking was missing around list traversal and hci_conn-related access. However, the patch does not demonstrate a strong LPE primitive such as controlled reclaim, controlled overwrite, type confusion, callback dispatch, or refcount takeover. Therefore it is not a strong Important candidate on current evidence, but it should not be auto-closed. ## 5. One-sentence report phrase Unlocked Bluetooth hci_sync lookups can race with connection parameter updates or teardown, creating a plausible stale pointer or UAF condition that can crash the kernel and warrants manual review despite no demonstrated privilege escalation primitive. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: this is a locking and lifetime fix around Bluetooth list and connection object lookups, with plausible UAF semantics and a common local attack surface, but without enough evidence to classify it as proven LPE. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: Bluetooth: hci_sync: hold hdev->lock for hci_conn_params lookups [ Upstream Commit: 8d892bec1dd134761cabec6ba23fe315d0f20f98 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8d892bec1dd134761cabec6ba23fe315d0f20f98 Changed files: net/bluetooth/hci_sync.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=8d892bec1dd134761cabec6ba23fe315d0f20f98 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68390 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68390 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:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 7 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).