From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-74539][MODERATE REGULAR] Bluetooth: ISO: lock sk in iso_sock_getname [ Upstream Date: Sat, 15 Aug 2026 13:25:07 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-74539 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: 4 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: 72d5bb1d77d7c3330146dc0cfd43f704c64b9594 List-Id: CVE: CVE-2026-74539 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: Bluetooth: ISO: lock sk in iso_sock_getname [ Upstream Commit: 72d5bb1d77d7c3330146dc0cfd43f704c64b9594 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72d5bb1d77d7c3330146dc0cfd43f704c64b9594 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74539 Analysis date: Sat, 15 Aug 2026 13:25:07 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline manual review recommended / Actionable Moderate candidate Manual review required: YES Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74539 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74539 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-2026-74539 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 ISO iso_sock_getname accessed iso_pi(sk) connection state without holding the socket lock even though iso_pi(sk) conn requires lock_sock protection. A local process operating an AF_BLUETOOTH ISO socket could race getpeername() or getsockname() with connection teardown or state changes, potentially leading to a stale connection pointer dereference, kernel crash, or use-after-free behavior. For the CVSS the PR:L is used because a local process must be able to operate an AF_BLUETOOTH ISO socket and trigger the local socket API path. The issue is not directly network reachable through IP networking. Bluetooth peer activity may influence connection state timing, but reliable triggering still depends on the local socket operation. Impact is at least local denial of service via kernel crash. In the paranoid interpretation, the UAF candidate around a kernel connection pointer can justify C:H/I:H/A:H for manual-review sensitivity over autoclosed false negatives.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / Actionable Moderate candidate (with actual score 4) YES REMOTE SIMPLEFIX NETWORK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Borderline manual review recommended / Actionable Moderate candidate** 2. Signal breakdown * Local unprivileged trigger: +1. A local process can potentially operate an AF_BLUETOOTH ISO socket and call getsockname or getpeername. * Memory corruption, weak/indirect corruption candidate: +1. The unlocked access to iso_pi(sk)->conn suggests a stale pointer or invalid object access risk, but no controlled reclaim, overwrite, callback dispatch, or type confusion is shown. * Real lifetime corruption: +1. The missing lock protects connection lifetime/state, so the bug is a race against connection teardown or state mutation. * Availability impact realistic: +1 in the conservative score. A stale connection pointer dereference can plausibly cause an Oops or kernel crash. * Reliable kernel crash / strong DoS: +1 only in the paranoid score. The patch context supports a crash concern, but no crash trace or reproducer is provided. * Broad/default/common subsystem: +1 only in the paranoid score. Bluetooth is common in many kernels, although ISO usage and hardware availability reduce exposure. * Hard or unreliable race / special timing required: -1. Triggering depends on racing getname with connection state change or teardown. 3. Reachability analysis The likely trigger is local, through AF_BLUETOOTH ISO socket operations. It is not directly IP network reachable. A Bluetooth peer may influence connection timing, but the vulnerable access is still reached through a local socket API call. Namespace behavior is product dependent, but this should generally be treated as PR:L rather than PR:H if unprivileged local users can create or operate the relevant Bluetooth sockets. Exposure requires Bluetooth ISO support and a relevant runtime setup, so it is not as broadly exposed as core TCP/IP or netfilter paths. 4. Severity interpretation This behaves like a race-dependent lifetime bug with weak UAF potential. The realistic impact is local denial of service through a crash. Theoretical memory corruption concern exists because a connection pointer is accessed without the required socket lock, but the patch does not show attacker-controlled reclaim, writable stale access, callback control, type confusion, or a direct privilege escalation primitive. Therefore it is not a Strong Important candidate from the patch alone, but it should not be auto-closed without manual review. 5. One-sentence report phrase Bluetooth ISO iso_sock_getname accessed connection state without holding the required socket lock, allowing a local AF_BLUETOOTH ISO socket user to race connection teardown and potentially trigger a stale pointer dereference or kernel crash. 6. Manual review recommendation MANUAL CHECK REQUIRED. Reason: race plus lifetime-sensitive connection pointer access is a UAF candidate, even though the currently supported practical impact is mainly local DoS and the exploitation primitive is not demonstrated. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: Bluetooth: ISO: lock sk in iso_sock_getname [ Upstream Commit: 72d5bb1d77d7c3330146dc0cfd43f704c64b9594 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72d5bb1d77d7c3330146dc0cfd43f704c64b9594 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=72d5bb1d77d7c3330146dc0cfd43f704c64b9594 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74539 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74539 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: 3 Paranoid ActionableScore: 4 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).