From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98295][MODERATE REGULAR] Bluetooth: coredump: Quiesce dump work on unregister [ Upstream Date: Sat, 10 Oct 2026 22:41:06 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98295 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 3 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 24af375d7d8aa5f698e4dc41317102f44114351a List-Id: CVE: CVE-2026-98295 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: Bluetooth: coredump: Quiesce dump work on unregister [ Upstream Commit: 24af375d7d8aa5f698e4dc41317102f44114351a Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=24af375d7d8aa5f698e4dc41317102f44114351a Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98295 Analysis date: Sat, 10 Oct 2026 22:41:06 -0400 ActionableScore: 3 ActionableScore lower bound: unknown Actionable bucket: Borderline / manual review recommended Manual review required: YES Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98295 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98295 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 REGULAR 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-2026-98295 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98295 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=4 LEGACY=MODERATE RESULT=DIFF (independent Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC) 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-416;CWE-362;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A race in the Bluetooth device coredump lifecycle allows dump_rx or dump_timeout work to remain active while an hci_dev is being unregistered and freed. Disconnecting or unregistering a controller during an active dump can therefore cause asynchronous work or a controller specific producer to access the released hci_dev, resulting in a use after free and at least a kernel crash. For the CVSS the PR:L in the paranoid score accounts for environments where a restricted service, container root, delegated Bluetooth capability, or virtual HCI access can initiate the affected lifecycle without full host administration. AC:H applies because successful triggering depends on winning the timing window between active coredump processing and device teardown. The issue is not directly reachable through ordinary remote Bluetooth traffic based on the supplied code, although a controlled controller or driver specific producer may influence the timing. Impact is at least local denial of service and may include confidentiality, integrity, or privilege escalation impact if the stale hci_dev access can be converted into controlled memory corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3) MAYBE REMOTE LOCK DANGER INIT NETWORK SKB DEBUGFS LINUS SYZBOT PACKET DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 PrimitiveClass=CLASS_B RealUAF=YES HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw conservative score: 3 * Conservative score: 3 * Raw paranoid score: 3 * Paranoid score: 3 * No floor or cap changed either score. * Final recommended bucket: **Borderline / manual review recommended**:: 2. Signal breakdown Positive signals: * +2 Real UAF / active lifetime violation. `dump_rx` and `dump_timeout` remain live after `hci_release_dev()` can free `hdev`, allowing asynchronous post-lifetime access. * +1 Reliable kernel crash / strong DoS. Accessing the freed `hci_dev` can produce a kernel fault, consistent with the syzbot report and the stated UAF mechanics. Negative signals: * No negative points. Host-admin privilege, difficult timing, rare hardware, and namespace restrictions are not positively established. Material non-awarded signals: * No controlled reclaim, attacker-shaped replacement object, arbitrary write, disclosure, callback control, or LPE is demonstrated. * Structured stale-object leverage is not awarded. Although `hci_dev` is active and structured, the supplied evidence does not show attacker control over reused storage or security-relevant fields consumed after reuse. * Attacker-influenced lifetime manipulation is not awarded because one attacker controlling the complete dump-plus-unregister sequence is not established. * Firmware-mediated influence is not awarded because attacker control of controller firmware or a malicious controller is not established. * No extra Availability point is awarded for the same crash. * No race penalty is applied merely because concurrent work and unregister are involved. The evidence does not establish a materially narrow or difficult-to-repeat timing window. * No privilege penalty is applied because the complete trigger privilege is unresolved. * B5-R does not apply because no retry-accumulated heap OOB write exists. * B3-PENDING does not apply because no shared-backing write is established. * B4-PENDING does not apply because there is no authorization decision or DENY-to-ALLOW transition. Repeated-release assessment: * `hci_release_dev()` may end the `hdev` lifetime. * A stale reference can survive in queued or delayed work. * No concrete second `put`, `release`, `free`, or refcount mutation on that exact stale reference is shown. * Concrete repeated release/refcount +1: not awarded. * Paranoid repeated-refcount leverage +1: not awarded. * REAL UAF FLOOR 5: not applied because there is no repeated lifetime mutation, controlled reuse, or meaningful post-reuse exploitation surface. 3. Reachability analysis The complete trigger requires an active Bluetooth devcoredump followed by unregister or disconnect while `dump_rx`, `dump_timeout`, or a producer remains active. Physical disconnect may contribute to teardown, but the evidence does not establish who can reliably initiate the dump and complete the full sequence. Below-host-admin triggering through virtual HCI, delegated Bluetooth management, a container, or namespace capabilities is not demonstrated. Conversely, host-admin-equivalent privilege is also not positively established because physical removal or controller-driven failure may participate. Therefore both host privilege and namespace scope remain unknown. Bluetooth hardware is common enough that no rare-hardware penalty applies. The race is associated with teardown, but queued work can remain active after unregister, so the evidence does not justify treating it as an exceptionally hard one-shot race. 4. Primitive and severity interpretation The exact primitive is an asynchronous post-teardown use-after-free of an active structured `hci_dev`. This is CLASS_B because a real kernel object lifetime violation exists. The stale use is tied to unregister and coredump shutdown, but it is performed by normal asynchronous coredump work rather than a demonstrated second destructor or refcount operation. The demonstrated consequence is kernel crash or DoS. Memory reuse may theoretically produce stronger effects, but controlled reclaim, meaningful stale-field exploitation, confidentiality impact, integrity impact, and privilege escalation are not established. ImportantCandidate is NO because this is presently a constrained teardown UAF without concrete reuse, repeated lifetime mutation, disclosure, directed corruption, or security-boundary bypass. AutoDowngradeAllowed is YES because the available evidence supports a crash-oriented CLASS_B issue and does not leave a specific Important-grade exploitation primitive unresolved. Likely operational severity is ordinary-to-borderline Moderate, with manual confirmation advisable due to the real UAF. 5. One-sentence report phrase A Bluetooth coredump teardown race can leave asynchronous dump work using a freed hci_dev and cause a local kernel crash, but no controlled reuse, arbitrary write, or privilege-escalation primitive is established. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Confirm whether unprivileged virtual HCI or delegated Bluetooth interfaces can reliably initiate both an active dump and device unregister, and inspect the stale worker operations for any write, callback, or refcount behavior beyond an ordinary fault. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: Bluetooth: coredump: Quiesce dump work on unregister [ Upstream Commit: 24af375d7d8aa5f698e4dc41317102f44114351a Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=24af375d7d8aa5f698e4dc41317102f44114351a Changed files: include/net/bluetooth/coredump.h net/bluetooth/coredump.c net/bluetooth/hci_core.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=24af375d7d8aa5f698e4dc41317102f44114351a ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98295 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98295 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:H/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: unknown Paranoid ActionableScore: 3 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: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).