From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-93805][MODERATE REGULAR] wifi: cfg80211: validate rx/tx MLME callback frame lengths before access [ Upstream Date: Thu, 24 Sep 2026 19:06:32 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-93805 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: 1 X-AL-KERNEL-Commit: 0ec738a0d361d7eb37188117166d201f9df622d3 List-Id: CVE: CVE-2026-93805 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: wifi: cfg80211: validate rx/tx MLME callback frame lengths before access [ Upstream Commit: 0ec738a0d361d7eb37188117166d201f9df622d3 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0ec738a0d361d7eb37188117166d201f9df622d3 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93805 Analysis date: Thu, 24 Sep 2026 19:06:32 -0400 ActionableScore: 2 ActionableScore lower bound: 1 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-2026-93805 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93805 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-2026-93805 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-93805 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L';CWE-125;*CWE-20;CWE-703;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.4';DESCR 'An out of bounds read in cfg80211 MLME management frame handling occurs because deauthentication disassociation and authentication subtype handlers can access fixed fields after only a frame control length check. A nearby wireless attacker or a malicious accessible access point may send a truncated management frame that is accepted by an affected driver such as mwifiex and reaches cfg80211 with no reason code body. This can cause a kernel out of bounds read and at least a local denial of service through a kernel warning or crash. For the CVSS the PR:N value is used because no account or local code execution on the target is required when an attacker can transmit crafted WiFi frames within radio range. The issue is network adjacent rather than generally Internet reachable. The paranoid score includes C:L because the bug is a confirmed kernel out of bounds read, but no write primitive or supported privilege escalation path is demonstrated. YES REQUIRES MANUAL CHECK';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES REMOTE OOB DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 1 * Conservative score: 1 * Raw paranoid score: 2 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate**:: No floor or cap was applied. 2. Signal breakdown Conservative signals: * +1 Firmware-mediated external influence. A nearby wireless attacker may transmit malformed management frames that are received by affected WiFi hardware and passed by firmware and a driver such as mwifiex into cfg80211. This is not ordinary direct IP network reachability because firmware and driver frame processing are material prerequisites. * +0 Limited out of bounds read. The patch establishes a two byte read past the supplied management frame length when a deauthentication or disassociation frame contains only the 24 byte management header and lacks the reason code. This is a real bounds-validation defect but does not itself establish a write, controlled reclaim, disclosure, or active object corruption primitive. Paranoid-only signal: * +1 Weak corruption and availability concern. The confirmed kernel OOB read can produce a sanitizer finding, warning, or potentially a fault depending on allocation layout and surrounding handling. This is not scored as a reliable kernel crash because the supplied patch does not establish a deterministic crash path. Important non-awarded signals: * Controlled reclaim is not demonstrated. * Arbitrary or directed kernel write is not demonstrated. * Real UAF or stale post-free object use is not established. * Confidentiality is not awarded. The patch shows an internal two byte OOB read but no user-visible, network-visible, or device-visible disclosure path. * Integrity is not awarded. No write primitive or security-sensitive state modification is shown. * Privilege escalation is not awarded. No attacker-controlled replacement, callback, type confusion, credential influence, or other LPE mechanism is established. * Direct remote network reachability is not awarded. The practical path is WiFi-adjacent and mediated by the affected wireless device firmware and driver. * Reliable kernel crash is not awarded. The patch fixes a read beyond the logical frame length, but does not demonstrate a deterministic panic or host-wide failure. * Broad subsystem exposure is not awarded. cfg80211 is broadly used, but the supplied concrete short-frame path is mwifiex-specific and the affected behavior of other drivers is not established. 3. Reachability analysis The evaluated attacker is a nearby WiFi attacker or an attacker controlling an accessible wireless access point. Such an attacker does not need an account, local code execution, CAP_NET_ADMIN, or host administrator privileges on the victim. Therefore HostAdminRequired is NO. The input identifies mwifiex as a concrete in-tree path. Its firmware processing accepts a frame with a four-address header and firmware length prefix, strips the prefix and addr4, and can pass a 24 byte three-address management header to cfg80211. A deauthentication or disassociation subtype then lacks the required two byte reason code. This is network-adjacent exposure through WiFi radio range, not generally Internet-reachable exposure. It depends on a vulnerable driver and firmware processing path receiving and forwarding the malformed management frame. No namespace capability, container privilege, prior host administrator setup, unusual boot parameter, or special attacker-controlled kernel object lifecycle is required by the shown path. The relevant practical prerequisite is physical WiFi proximity or access to the local wireless environment. No race is involved. The malformed frame can be supplied repeatedly, but repeatability alone does not create an exploitation primitive beyond the same bounded read. 4. Primitive and severity interpretation The exact primitive is a bounded out of bounds read of fixed management-frame fields. Before the fix, cfg80211_rx_mlme_mgmt and cfg80211_tx_mlme_mgmt checked only that at least two bytes existed before reading frame_control. They then dispatched deauthentication, disassociation, or authentication frames to handlers that assume subtype-specific fixed fields exist. For the concrete deauthentication example, cfg80211_process_deauth reads u.deauth.reason_code at offset 24 from a 24 byte management frame. This is a two byte access beyond the supplied buffer length. This is not a UAF, double release, refcount mutation, RCU lifetime issue, controlled object replacement, or active structured-object stale-use case. The primitive is therefore CLASS_C, representing invalid-state and limited OOB-read behavior with possible DoS effects but without an independently useful corruption primitive. The demonstrated consequence is an invalid kernel memory read. A warning, sanitizer report, or crash is plausible depending on allocation and instrumentation conditions, but a reliable kernel panic is not demonstrated by the patch. A confidentiality effect remains speculative because no data is copied back to the attacker or exposed through a documented observable interface. Integrity and privilege escalation are unsupported because there is no write or control-flow primitive. ImportantCandidate is NO because the OOB read is short and fixed, with no demonstrated disclosure, write, replacement, reclaim, lifetime corruption, or security-boundary bypass. AutoDowngradeAllowed is YES because the evidence supports a constrained malformed-frame handling defect rather than unresolved active kernel corruption leverage. Manual review remains recommended because the issue is externally reachable from the local wireless environment and affected driver paths should be checked in the target product. 5. One-sentence report phrase A nearby WiFi attacker may trigger a limited out of bounds read in cfg80211 by transmitting a truncated management frame that an affected driver forwards without the subtype required fixed fields, but the supplied evidence supports at most a warning or denial of service and does not establish disclosure, corruption, or privilege escalation. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Review whether the target uses mwifiex or another driver and firmware path that can forward truncated management frames to cfg80211. The patch confirms a kernel OOB read, but the supplied evidence does not establish a reliable crash, disclosure path, or stronger exploitation primitive. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: cfg80211: validate rx/tx MLME callback frame lengths before access [ Upstream Commit: 0ec738a0d361d7eb37188117166d201f9df622d3 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0ec738a0d361d7eb37188117166d201f9df622d3 Changed files: net/wireless/mlme.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=0ec738a0d361d7eb37188117166d201f9df622d3 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93805 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93805 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:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L The Best / paranoid CVSS score: 5.4 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: 1 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).