From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-63871][LOW] Bluetooth: ISO: Fix data-race on iso_pi fields in hci_get_route calls [ Upstream Date: Sun, 19 Jul 2026 11:29:05 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-63871 X-AL-KERNEL-Priority: LOW X-AL-KERNEL-Severity: LOW X-AL-KERNEL-Base-Severity: LOW X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 1 X-AL-KERNEL-ActionableScore-Lower: 0 X-AL-KERNEL-Commit: 9798f7d41d85ff763afd1f1cc0533b5c416c8348 List-Id: CVE: CVE-2026-63871 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: Bluetooth: ISO: Fix data-race on iso_pi fields in hci_get_route calls [ Upstream Commit: 9798f7d41d85ff763afd1f1cc0533b5c416c8348 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9798f7d41d85ff763afd1f1cc0533b5c416c8348 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-63871 Analysis date: Sun, 19 Jul 2026 11:29:05 -0400 ActionableScore: 1 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: Bluetooth ISO route lookup could read socket address fields concurrently with local connect or setsockopt updates, causing a low impact data race and possible connection misbehavior without evidence of memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-63871 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-63871 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: LOW Manual review required: NO A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-63871 LOW CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L';CWE-362;CWE-667;CWE-662;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '3.6';DESCR 'Bluetooth ISO code could read iso_pi socket address fields without lock_sock while another local thread changes the same fields through connect or setsockopt. This creates a data race in hci_get_route input handling and may lead to inconsistent route selection, failed connection setup, or other low impact socket level misbehavior. For the CVSS the PR:L is used because reliable triggering requires a local process that can operate on the same Bluetooth ISO socket. The issue is not directly network reachable because a remote Bluetooth peer does not control concurrent modification of these local socket fields. Impact is mainly local denial of service or connection confusion, with no supported UAF, OOB access, or privilege escalation primitive.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) YES REMOTE KASAN LOCK RACE NETWORK DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 ActionableScoreLower=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 1 * Final recommended bucket: **Ordinary Moderate / Low-like** ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1. A local process can potentially operate on a Bluetooth ISO socket and race connect or setsockopt on the same socket. * Hard or unreliable race / special timing required: -1. The issue is a KCSAN-reported data race requiring concurrent access to the same socket fields. * No memory corruption signal: +0. The patch snapshots inline socket address fields and does not show UAF, OOB access, double free, stale callback, refcount abuse, or object replacement. * No strong DoS signal: +0. The likely effect is failed routing, failed connection setup, or socket-level confusion, not a demonstrated kernel crash. * No confidentiality or privilege-escalation signal: +0. No disclosure path, arbitrary read/write, or LPE primitive is supported by the patch. Paranoid additional signal: * Availability impact realistic: +1. A racy route lookup can plausibly cause connection failure or local Bluetooth ISO socket disruption, but this remains low impact and not system-wide. ## 3. Reachability analysis The bug is locally triggerable by code operating on the same Bluetooth ISO socket while another thread changes address-related ISO socket fields through connect or setsockopt. A remote Bluetooth peer does not directly control the concurrent modification of iso_pi fields, so this is not realistically network-triggerable. Namespace or container effects do not materially raise severity unless the environment deliberately exposes Bluetooth socket access to untrusted workloads. The affected Bluetooth ISO path is not a broad default server-side attack surface and requires Bluetooth ISO functionality and local socket activity. Call-site confidence: high. The patch shows all affected call sites and the fixed pattern clearly. ## 4. Severity interpretation This behaves like an ordinary Low or low-end Moderate synchronization bug. Theoretical impact is limited to inconsistent route selection, failed connection setup, or local connection-state confusion. There is no realistic evidence of memory corruption, privilege escalation, sensitive data exposure, or a reliable kernel crash. It should not be treated as an Actionable Moderate or Important candidate. ## 5. One-sentence report phrase Bluetooth ISO route lookup could read socket address fields concurrently with local connect or setsockopt updates, causing a low impact data race and possible connection misbehavior without evidence of memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed for practical triage because it is a local same-socket data race with no demonstrated UAF, OOB access, strong DoS, information leak, or privilege-escalation primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: Bluetooth: ISO: Fix data-race on iso_pi fields in hci_get_route calls [ Upstream Commit: 9798f7d41d85ff763afd1f1cc0533b5c416c8348 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9798f7d41d85ff763afd1f1cc0533b5c416c8348 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=9798f7d41d85ff763afd1f1cc0533b5c416c8348 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-63871 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-63871 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:L The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L The Best / paranoid CVSS score: 3.6 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: 0 Paranoid ActionableScore: 1 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: LOW KPANIC detected for this report: NO Published priority for this report (same as in Subject): LOW 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).