From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99012][MODERATE 7.0] Bluetooth: ISO: Serialize concurrent connect calls [ Upstream Date: Tue, 27 Oct 2026 00:25:56 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99012 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: 9b6ed57eb8c892ee7566b8c1bd06fdd0053b53de List-Id: CVE: CVE-2026-99012 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: Bluetooth: ISO: Serialize concurrent connect calls [ Upstream Commit: 9b6ed57eb8c892ee7566b8c1bd06fdd0053b53de Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9b6ed57eb8c892ee7566b8c1bd06fdd0053b53de Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99012 Analysis date: Tue, 27 Oct 2026 00:25:56 -0400 ActionableScore: 5 ActionableScore lower bound: 4 Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review Manual review required: YES Summary: Concurrent Bluetooth ISO connects can strand a connection back-pointer and cause an asynchronous refcount operation on a freed socket. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99012 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99012 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-2026-99012 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-99012 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=4 LEGACY=MODERATE_KPANIC RESULT=SAME (final reconciliation agrees; DECISION: both 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-362;*CWE-416;CWE-667;*CWE-664;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'A race between concurrent Bluetooth ISO connect calls can replace iso_pi sk conn while an older CIS or BIS connection still retains its conn sk back pointer. Later asynchronous teardown can call iso_sock_hold through the stale connection after the socket has been released, producing a KASAN confirmed slab use after free. For the CVSS the PR:L reflects that an attacker needs local code execution and access to a Bluetooth ISO socket and the same socket descriptor must be used by concurrent callers. AC:H reflects the required race between connect, attachment, socket release, and an asynchronous HCI callback. The confirmed UAF can crash the kernel and may affect reclaimed slab memory, but reliable privilege escalation depends on controlled object reuse and is not demonstrated. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 7 and the production ActionableScore returned 5 with recommendation Actionable Moderate / Strong Important candidate requiring manual review. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to IMPORTANT because the CVSS score, vector or bug class threshold rule was applied. KP and FD specialist checks stage IMPORTANT to MODERATE_KPANIC because FD false positive review allowed a downgrade. The legacy KP specialist produced a review artifact and its decision was processed by the applicable KP rules. The legacy FD or DH downgrade specialist produced a review artifact and its decision was processed by the applicable downgrade and preservation rules. Exact triggered rule markers were INCREASED_TO_HIGH_BASED_ON_GUESSCVSS and DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 4 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is MODERATE_KPANIC.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5) MAYBE REMOTE OOB LOCK DANGER RACE UAF NETWORK HARDWARE LINUS TEST KPANIC KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=4 PrimitiveClass=CLASS_B RealUAF=YES HostAdminRequired=NO NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=YES ManualReview=REQUIRED AutoDowngradeAllowed=NO RequiresHostUID0=NO AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 4. * Conservative score: 4; the Real-UAF floor 4 is satisfied but does not change the score. * Raw paranoid score: 5. * Paranoid score: 5; no floor or cap changes it. * Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**:: 2. Signal breakdown * +2 Real UAF: concurrent connects can strand an old `conn->sk`; asynchronous teardown later reaches the freed socket, confirmed by KASAN in `iso_sock_hold()`. * +1 Reliable kernel crash/strong DoS: dereferencing or modifying the freed socket can fault the kernel. * +1 Local below-host-admin trigger: supplied evidence supports a low-privilege local actor with Bluetooth ISO socket access and concurrent use of the same descriptor. * +1 Attacker-influenced lifetime manipulation: the actor drives concurrent destination/connection replacement and socket release, directly creating the stale back-pointer. * -1 Hard timing: exploitation requires overlap among concurrent connect, release, and asynchronous HCI completion/teardown. * Paranoid +1: `iso_sock_hold()` performs a lifetime/refcount operation through the freed structured socket, providing a concrete post-lifetime mutation beyond a passive stale read. No concrete repeated release is shown, so its dedicated +1 and floor 5 were not applied. Controlled reclaim, attacker-shaped replacement contents, arbitrary write, disclosure, LPE, and extra availability impact are not shown. This is not B5-R, B3-PENDING, or an authorization bypass. 3. Reachability analysis The assessed actor is a local low-privilege process able to open/use a Bluetooth ISO socket, share one descriptor between threads, race `connect()`, and close the socket. No host-admin capability or host UID 0 requirement is evidenced. Namespace capability scope is not established. Bluetooth hardware/controller activity and asynchronous HCI completion are required, but the evidence does not establish rare hardware. The race is materially timing-sensitive, though retries appear feasible. 4. Primitive and severity reading This is an active structured-object UAF, not fixed stale storage: an obsolete ISO connection retains a socket back-pointer after another connection replaces the socket attachment. A later callback calls `iso_sock_hold()` after socket destruction, touching freed lifetime state. The shown effects are slab UAF and plausible host crash. Reclaim control and a useful non-crash write target remain unproven. CLASS_B is appropriate. ImportantCandidate is YES because a below-host-admin actor can create an active-object UAF with a concrete post-free lifetime operation whose exploit leverage requires review. Auto-downgrade is unsafe despite the absence of proven LPE. 5. One-sentence report phrase Concurrent Bluetooth ISO connects can strand a connection back-pointer and cause an asynchronous refcount operation on a freed socket. 6. Manual review advice MANUAL CHECK REQUIRED Review reclaim behavior and whether `iso_sock_hold()` can mutate attacker-influenced replacement slab objects rather than only causing a fault. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: Bluetooth: ISO: Serialize concurrent connect calls [ Upstream Commit: 9b6ed57eb8c892ee7566b8c1bd06fdd0053b53de Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9b6ed57eb8c892ee7566b8c1bd06fdd0053b53de Changed files: net/bluetooth/iso.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=9b6ed57eb8c892ee7566b8c1bd06fdd0053b53de ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99012 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99012 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:L/I:L/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).