From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-74324][MODERATE REGULAR] wifi: mt76: mt7925: validate skb length in testmode query [ Upstream Date: Sat, 15 Aug 2026 16:55:49 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-74324 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: 3 X-AL-KERNEL-ActionableScore-Lower: 1 X-AL-KERNEL-Commit: c386e90a7ce8ddec9f038e9437661a2821b0ce89 List-Id: CVE: CVE-2026-74324 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: wifi: mt76: mt7925: validate skb length in testmode query [ Upstream Commit: c386e90a7ce8ddec9f038e9437661a2821b0ce89 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c386e90a7ce8ddec9f038e9437661a2821b0ce89 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74324 Analysis date: Sat, 15 Aug 2026 16:55:49 -0400 ActionableScore: 3 ActionableScore lower bound: 1 Actionable bucket: Borderline Moderate / manual review required, not Important Manual review required: YES Summary: A missing skb length check in the mt7925 testmode query path can cause an OOB read from a short firmware response, with the over-read data copied back to userspace, resulting in a local kernel information disclosure risk. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74324 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74324 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-2026-74324 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N';CWE-125;*CWE-200;*CWE-20;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '5.5';DESCR 'An out of bounds read in mt7925_tm_query can occur because the driver copies MT7925_EVT_RSP_LEN bytes from skb data plus 8 without first checking that the firmware response skb is at least 520 bytes long. If a short firmware response is returned, kernel memory beyond the valid skb data can be copied into evt_resp and later returned to userspace through nla_put. For the CVSS the PR:L value is used in the paranoid score because testmode access may be delegated to a local service, container root, or a user with network administration capability rather than requiring full host root. The issue is not network reachable and requires local interaction with the WiFi testmode control path on a system with the mt7925 driver and suitable hardware. Impact is primarily confidentiality loss through kernel memory disclosure. Integrity impact is not indicated because the primitive is an out of bounds read rather than a write. Availability impact is not the main concern unless debug hardening converts the over read into a warning or fault.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate / manual review required, not Important (with actual score 2) SKIP CVE-2026-74324 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE REMOTE DANGER SIMPLEFIX NETWORK SKB TEST DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 ActionableScoreLower=1 ## 1. ActionableScore * Conservative score: **1** * Paranoid score: **3** * Final recommended bucket: **Borderline Moderate / manual review required, not Important**:: ## 2. Signal breakdown Conservative signals: * **Firmware-mediated external influence: +1**. The short skb depends on firmware response behavior, not direct remote packet parsing. * **Confidentiality impact plausible: +1**. The over-read bytes are copied into `evt_resp` and returned to userspace via `nla_put()`. * **Requires CAP_NET_ADMIN or equivalent in typical deployments: -2**. nl80211 testmode access is normally privileged. * **Rare hardware/configuration path: -1**. Requires mt7925 hardware, mt76 mt7925 driver, and testmode support. Conservative raw score is below 1, but I keep **1** because there is a concrete user-visible kernel memory disclosure path. Paranoid signals: * **Firmware-mediated external influence: +1**. A malformed or short firmware response can trigger the issue. * **Local reduced-privilege trigger concern: +1**. In some deployments, testmode or network administration may be delegated to a service, container root, or non-full-root operator. * **Confidentiality impact plausible: +1**. The primitive is an OOB read with userspace disclosure. * No LPE signal is awarded. The primitive is read-only OOB, not write, UAF, refcount abuse, or object replacement. * No generic strong memory corruption signal is awarded. This is not an OOB write or lifetime corruption. ## 3. Reachability analysis The bug is triggered through the mt7925 WiFi testmode query path. In normal Linux deployments, this is local control-plane access and usually requires `CAP_NET_ADMIN` or equivalent privileges. It is not network reachable by ordinary WiFi traffic. Namespaces or containers can matter if a container root or service account receives delegated network administration capabilities. In that case the practical PR may be closer to reduced-privilege local access rather than full host root, which supports the paranoid score. The path is hardware and configuration dependent. It requires an affected MediaTek mt7925 device, the relevant driver, testmode support, and a short firmware response. ## 4. Severity interpretation This behaves like a **manual-review Moderate**, not an Important candidate by default. The concrete primitive is a kernel OOB read with disclosure to userspace, so it is more serious than a pure validation cleanup or crash-only bug. However, there is no demonstrated write primitive, UAF reclaim, type confusion, callback control, or privilege escalation path. The realistic impact is local kernel memory disclosure from a privileged or semi-privileged WiFi testmode path. The theoretical worst case is broader confidentiality exposure if the returned bytes contain sensitive adjacent kernel data and the interface is reachable by a reduced-privilege actor. ## 5. One-sentence report phrase A missing skb length check in the mt7925 testmode query path can cause an OOB read from a short firmware response, with the over-read data copied back to userspace, resulting in a local kernel information disclosure risk. ## 6. Manual review recommendation **MANUAL CHECK REQUIRED** Reason: this is a concrete OOB read with a userspace disclosure path. Manual review should confirm whether `CONFIG_NL80211_TESTMODE` is enabled, who can access testmode on the target product, and whether short mt7925 firmware responses can be reliably induced. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: wifi: mt76: mt7925: validate skb length in testmode query [ Upstream Commit: c386e90a7ce8ddec9f038e9437661a2821b0ce89 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c386e90a7ce8ddec9f038e9437661a2821b0ce89 Changed files: drivers/net/wireless/mediatek/mt76/mt7925/testmode.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=c386e90a7ce8ddec9f038e9437661a2821b0ce89 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74324 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74324 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:N/A:N The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N The Best / paranoid CVSS score: 5.5 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: 3 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).