From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-93789][MODERATE REGULAR] wifi: iwlwifi: bound aligned TLV advance in FW parser [ Upstream Date: Thu, 24 Sep 2026 20:12:29 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-93789 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: 528fa9eb14c209533ca26958b76da55e0ce239d8 List-Id: CVE: CVE-2026-93789 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: wifi: iwlwifi: bound aligned TLV advance in FW parser [ Upstream Commit: 528fa9eb14c209533ca26958b76da55e0ce239d8 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=528fa9eb14c209533ca26958b76da55e0ce239d8 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93789 Analysis date: Thu, 24 Sep 2026 20:12:29 -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-2026-93789 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93789 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-2026-93789 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-93789 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:H/UI:N/S:U/C:L/I:N/A:H';CWE-190;CWE-125;*CWE-20;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'A malformed aligned TLV length in the iwlwifi firmware parser can cause an unsigned length underflow after the original TLV length check succeeds. The parser can then advance beyond the firmware image and interpret out of bounds memory as subsequent TLVs, which may cause a driver failure or kernel denial of service. For the CVSS the PR:H because reliable triggering normally requires control over the firmware image loaded by the host. The issue is not network reachable through normal WiFi packet processing. Firmware images are normally administrator controlled and commonly signature checked, making practical exploitation difficult. The patch context demonstrates an out of bounds read condition but does not demonstrate an out of bounds write, use after free, information disclosure, or privilege escalation primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) YES REMOTE OOB SIMPLEFIX NETWORK 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 Weak indirect memory-safety concern. A malformed TLV can pass the original length validation but fail after four-byte alignment. The unsigned remaining-length subtraction can underflow, and parsing can continue beyond the firmware image. * +0 Reliable kernel crash. The patch prevents out-of-bounds parsing, but the supplied evidence does not demonstrate a reproducible kernel panic, host-wide crash, or persistent availability failure. * +0 Confidentiality. No path is shown that copies out-of-bounds bytes to userspace, a network peer, device-visible memory, or another observable output. * +0 Integrity. No out-of-bounds write, attacker-controlled target, active-object corruption, or other write primitive is established. * +0 Remote reachability. Firmware-image parsing is not reached directly by ordinary WiFi packet traffic. * +0 Local unprivileged trigger. The supplied patch does not establish that an ordinary user can replace or supply the firmware image used by iwlwifi. * No host-admin penalty was applied. Reliable firmware-image control likely requires privileged filesystem or firmware-loading control, but the complete privilege boundary and signature-verification behavior are not supplied. * No firmware-mediated external-influence point was awarded. The input is a host-loaded firmware blob, not attacker-controlled data received from a remote WiFi peer. * No UAF, double free, refcount mutation, controlled reclaim, callback influence, structured stale-object leverage, arbitrary write, or privilege-escalation primitive is established. 3. Reachability analysis The vulnerable function parses an iwlwifi firmware image during driver firmware loading. A trigger requires a malformed firmware TLV whose unaligned length fits in the remaining input but whose aligned length exceeds it. The supplied context does not establish who can provide such a firmware image in the evaluated deployment. In normal distributions, firmware files are host-admin controlled and Intel wireless firmware is commonly authenticated or signature checked, but those deployment facts are not enough to set HostAdminRequired=YES without the exact firmware-loading and verification path. No network namespace, user namespace, or delegated capability path is shown. NamespaceScopedPrivilege is therefore UNKNOWN. No special hardware beyond an affected Intel wireless adapter is required, but the patch alone does not show a remote attacker-controlled delivery path. 4. Primitive and severity interpretation The concrete defect is an integer-underflow-driven out-of-bounds parser advance. After `len -= ALIGN(tlv_len, 4)` underflows, `data` can advance beyond the firmware buffer and subsequent parser iterations can interpret unrelated memory as TLV data. This is an invalid parser-state and out-of-bounds-read concern, not a demonstrated active-object lifetime bug. There is no real UAF, no stale reference, no second lifetime operation, no controlled replacement, and no demonstrated memory write. The appropriate class is CLASS_C because the established consequence is invalid parsing and possible driver failure rather than an independently useful kernel-corruption primitive. The patch does not establish a disclosure sink, attacker-controlled write, privilege escalation path, or direct remote WiFi trigger. The issue should not be treated as an Important candidate. Auto-downgrade is allowed because the currently established primitive is constrained and lacks unresolved active-object or security-boundary leverage. 5. One-sentence report phrase A malformed aligned TLV length in the iwlwifi firmware parser can underflow the remaining input length and cause out-of-bounds firmware parsing, but the supplied patch does not establish a write primitive, disclosure, privilege escalation, or direct remote trigger. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Confirm the firmware trust chain for the affected deployment, including whether unsigned or locally replaceable firmware can reach `iwl_parse_tlv_firmware`, and inspect downstream TLV handlers for a concrete dereference, disclosure, or write consequence after parser desynchronization. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: iwlwifi: bound aligned TLV advance in FW parser [ Upstream Commit: 528fa9eb14c209533ca26958b76da55e0ce239d8 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=528fa9eb14c209533ca26958b76da55e0ce239d8 Changed files: drivers/net/wireless/intel/iwlwifi/iwl-drv.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=528fa9eb14c209533ca26958b76da55e0ce239d8 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-93789 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93789 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:N/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H The Best / paranoid CVSS score: 4.7 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: 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).