From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-93791][MODERATE REGULAR] wifi: iwlwifi: mvm: add a check on the tid coming from the firmware [ Upstream Date: Thu, 24 Sep 2026 20:20:41 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-93791 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: 2 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: 0b5325a0771674f1d65618de7db3df9d49186a12 List-Id: CVE: CVE-2026-93791 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: wifi: iwlwifi: mvm: add a check on the tid coming from the firmware [ Upstream Commit: 0b5325a0771674f1d65618de7db3df9d49186a12 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0b5325a0771674f1d65618de7db3df9d49186a12 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93791 Analysis date: Thu, 24 Sep 2026 20:20:41 -0400 ActionableScore: 2 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-2026-93791 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93791 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-2026-93791 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-93791 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:L/I:L/A:H';CWE-129;CWE-125;*CWE-787;*CWE-20;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '6.4';DESCR 'An unchecked firmware supplied TID value in an iwlwifi BA notification is used as an index into mvmsta tid_data. A malformed value can access memory outside the tid_data array in kernel context and may cause a kernel crash or limited confidentiality and integrity impact depending on the adjacent object layout and later accesses. For the CVSS the PR:N in the paranoid score assumes an adjacent attacker can cause the WiFi firmware to generate a malformed BA notification without local access. This remote adjacent path is not proven by the patch and requires manual verification of firmware notification parsing and TID derivation. The base score uses PR:H because the directly supported trigger requires compromised or replaced firmware which is normally an administrative capability. The issue is not demonstrated as Internet reachable. Impact is at least a local denial of service and potential out of bounds kernel memory access. YES REQUIRES MANUAL CHECK';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES REMOTE OOB SIMPLEFIX NETWORK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 2 * Conservative score: 2 * Raw paranoid score: 2 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate**:: No floor or cap was applied. 2. Signal breakdown * +1 Weak indirect corruption candidate. The firmware supplied u8 TID is used as an unchecked index into mvmsta->tid_data before the added bounds check. This establishes an out of bounds array access candidate in kernel context. * +1 Broadly exercised driver path. iwlwifi BA notifications and per TID transmission state are normal runtime functionality on affected Intel WiFi devices using aggregation. Non-awarded signals: * No concrete out of bounds write is demonstrated by the supplied diff. The visible patch proves that an out of range array index was possible, but the subsequent tid_data field accesses are not included. * No controlled attacker payload or target selection is demonstrated. * No kernel crash, panic, information disclosure, integrity impact, privilege escalation, or arbitrary read or write is demonstrated. * Remote or WiFi adjacent reachability is not established. The value is firmware controlled, but the supplied evidence does not show that an over the air attacker can cause firmware to emit an invalid TID. * Firmware mediated external influence is not awarded because external influence over ba_notif->tid is not established. * No UAF, stale object use, repeated release, refcount mutation, callback control, or object replacement exists in the supplied evidence. * No privilege penalty is applied. Host admin privilege may be needed to replace firmware, but that prerequisite is not proven as the only way to trigger the invalid notification. Relevant CWE candidates are CWE-129 Improper Validation of Array Index, CWE-125 Out of Bounds Read, and potentially CWE-787 Out of Bounds Write only if later unseen tid_data accesses modify fields through the invalid pointer. 3. Reachability analysis The vulnerable input is received from Intel WiFi firmware through a BA notification. The patch does not show that a remote WiFi peer can directly control the firmware notification TID value. Normal IEEE 802.11 TID values are normally range limited, so a malformed value may instead require faulty, compromised, or otherwise unexpected firmware behavior. The evaluated attacker model is unresolved. A host administrator may be able to replace or manipulate firmware, but the supplied material does not establish that this is required for every trigger. Conversely, it does not establish that an ordinary local user or adjacent wireless attacker can trigger the complete path. No relevant namespace capability chain is shown. Namespace scoped privilege is therefore UNKNOWN. There is no demonstrated prior host setup requirement beyond use of an affected Intel iwlwifi device and normal BA notification handling. 4. Primitive and severity interpretation The exact established primitive is an unchecked firmware supplied array index. An invalid TID can select memory outside the mvmsta->tid_data array before the new bounds check rejects it. This is not a UAF and does not involve a lifetime violation. The patch is a validation fix and the supplied context does not show the later use of the indexed tid_data element. Therefore, the available evidence supports an invalid access or crash concern, but not a controlled overwrite, disclosure path, controlled type confusion, or privilege escalation primitive. This is CLASS_C because the established behavior is an invalid state and potential out of bounds access without independently useful exploitation leverage. ImportantCandidate is NO because neither a strong corruption primitive nor meaningful attacker-controlled reuse or write leverage is demonstrated. AutoDowngradeAllowed is YES because the available evidence supports a constrained invalid-access concern and does not leave a concrete unresolved lifetime, ownership, authorization, or controlled-corruption primitive. Likely operational severity is ordinary Moderate or lower. The issue should still be reviewed against the complete iwl_mvm_rx_ba_notif function because a later write through tid_data would materially change the primitive classification. 5. One-sentence report phrase An unchecked firmware supplied TID value can index outside the iwlwifi tid_data array, potentially causing an invalid kernel memory access, but remote WiFi attacker control and a controlled out of bounds write are not established by the supplied patch. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Review the complete iwl_mvm_rx_ba_notif function and firmware notification origin to determine whether the invalid tid_data pointer is later written through and whether malformed BA notifications can be induced by adjacent WiFi traffic rather than requiring compromised firmware. 7. Call-site confidence Call-site confidence: low ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: iwlwifi: mvm: add a check on the tid coming from the firmware [ Upstream Commit: 0b5325a0771674f1d65618de7db3df9d49186a12 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0b5325a0771674f1d65618de7db3df9d49186a12 Changed files: drivers/net/wireless/intel/iwlwifi/mvm/tx.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=0b5325a0771674f1d65618de7db3df9d49186a12 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93791 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93791 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:L/I:L/A:H The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H The Best / paranoid CVSS score: 6.4 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: 2 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).