From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-93804][MODERATE REGULAR] wifi: mac80211: ibss: wait for in-flight TX on disconnect [ Upstream Date: Thu, 24 Sep 2026 14:08:24 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-93804 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: 1 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 20a3fb5e1a95caa34896853ca17a50d21c754969 List-Id: CVE: CVE-2026-93804 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: wifi: mac80211: ibss: wait for in-flight TX on disconnect [ Upstream Commit: 20a3fb5e1a95caa34896853ca17a50d21c754969 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=20a3fb5e1a95caa34896853ca17a50d21c754969 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93804 Analysis date: Thu, 24 Sep 2026 14:08:24 -0400 ActionableScore: 1 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93804 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93804 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: NO A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-93804 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-93804 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-362;CWE-667;CWE-703;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'A race condition in the mac80211 IBSS disconnect path can allow packet transmission to continue while or after the driver is instructed to leave the IBSS. In iwlwifi this may result in access to invalid transmit queues and can cause a driver failure or kernel denial of service. For the CVSS the PR:N value is used for the paranoid score because a nearby wireless attacker may be able to influence IBSS disconnect related events without local access, although reliable triggering also requires a narrow timing window and concurrent transmit activity. The issue is network adjacent rather than Internet reachable. No confidentiality or integrity impact is established because the patch shows a synchronization race around transmit queue lifetime but does not demonstrate a use after free, out of bounds access, information leak, or write primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) YES REMOTE INIT SIMPLEFIX RACE HARDWARE PACKET DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 1 * Conservative score: 1 * Raw paranoid score: 1 * Paranoid score: 1 * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 Reliable kernel or driver denial of service: The patch documents transmit processing reaching the driver while or after the driver leaves IBSS. The iwlwifi consequence is use of invalid TX queues, which can realistically cause a driver failure and may cause kernel-level availability loss. * No remote reachable bonus: The patch does not establish that unauthenticated wireless traffic alone reliably initiates the complete IBSS disconnect and concurrent TX sequence. * No local unprivileged trigger bonus: The supplied material does not establish that an ordinary user can create and control the complete IBSS interface, disconnect, and TX sequence without elevated network-management privileges. * No race penalty: The code is a cross-CPU race, but the supplied evidence does not establish a rare one-shot or externally uncontrollable timing condition sufficient for a negative point. * No UAF signal: No object free, stale dereference, post-free access, second release, refcount mutation, OOB access, or memory overwrite is shown. * No controlled reclaim, arbitrary write, callback control, information disclosure, integrity impact, or privilege escalation primitive is demonstrated. * No extra availability point: The possible driver failure or kernel DoS is counted once only. 3. Reachability analysis The vulnerable sequence occurs while a mac80211 IBSS interface is disconnecting. The race requires in-flight or concurrent TX processing to reach the driver after carrier state is disabled and while the driver is leaving the IBSS. A local actor with sufficient control over the wireless interface and IBSS state may be able to exercise the path. However, the supplied patch does not establish the exact privilege boundary for creating or managing the required IBSS interface, initiating disconnect, and generating the concurrent transmit workload. Therefore HostAdminRequired is UNKNOWN. A nearby wireless peer may influence IBSS-related events, including events that could contribute to connection loss or disconnect handling. However, the supplied evidence does not establish that a nearby attacker can reliably cause the complete disconnect plus concurrent TX sequence without local privileges. This is therefore not scored as directly network reachable or as an attacker-controlled network-adjacent trigger. No namespace-scoped complete trigger chain is established. The presence of wireless interfaces or network namespaces alone would not prove that all required device and IBSS-management operations are available below host administration. 4. Primitive and severity interpretation The demonstrated defect is an ordering and synchronization failure in the IBSS teardown path. `netif_carrier_off()` and a guaranteed `synchronize_net()` must occur before the driver is notified that the interface has left IBSS, so that in-flight packet processing cannot submit TX work against driver queues that are no longer valid. This is not a real UAF. The patch does not show freed memory being accessed, stale object reuse, a refcount error, a double release, an invalid callback, an OOB operation, or an attacker-controlled memory corruption primitive. The affected state is active transmit and driver queue state, but the established consequence is invalid-state driver interaction rather than structured post-lifetime object consumption. The practical impact is driver failure or denial of service. Privilege escalation, confidentiality impact, integrity impact, and arbitrary kernel memory access remain speculative and are not supported by the patch. PrimitiveClass is CLASS_C because the evidence supports invalid queue access and possible crash or DoS behavior without an independently useful kernel-corruption primitive. ImportantCandidate is NO and AutoDowngradeAllowed is YES because no unresolved Class A or Class B memory-lifetime primitive is present. 5. One-sentence report phrase A cross CPU race during mac80211 IBSS disconnect can submit in flight TX work after the driver leaves the IBSS, causing iwlwifi to access invalid transmit queues and potentially resulting in driver or kernel denial of service. 6. Manual review recommendation MANUAL CHECK RECOMMENDED The patch establishes a race involving active driver TX queues, but the actual consequence depends on the affected wireless driver and the complete attacker reachability of IBSS disconnect events is not established. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: mac80211: ibss: wait for in-flight TX on disconnect [ Upstream Commit: 20a3fb5e1a95caa34896853ca17a50d21c754969 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=20a3fb5e1a95caa34896853ca17a50d21c754969 Changed files: net/mac80211/ibss.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=20a3fb5e1a95caa34896853ca17a50d21c754969 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93804 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93804 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:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 5.3 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: 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: 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).