From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-64275][LOW] Input: elan_i2c - prevent division by zero and arithmetic underflow Date: Sat, 25 Jul 2026 13:53:07 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-64275 X-AL-KERNEL-Priority: LOW X-AL-KERNEL-Severity: LOW X-AL-KERNEL-Base-Severity: LOW X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 2 X-AL-KERNEL-ActionableScore-Lower: 1 X-AL-KERNEL-Commit: 59d4cc5e7a9785e4bdc9c55273274c6b49d4b58d List-Id: CVE: CVE-2026-64275 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: Input: elan_i2c - prevent division by zero and arithmetic underflow Commit: 59d4cc5e7a9785e4bdc9c55273274c6b49d4b58d Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=59d4cc5e7a9785e4bdc9c55273274c6b49d4b58d Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64275 Analysis date: Sat, 25 Jul 2026 13:53:07 -0400 ActionableScore: 2 ActionableScore lower bound: 1 Actionable bucket: Ordinary Moderate / Low-like Manual review required: YES Summary: Malformed Elan I2C touchpad firmware or platform parameters can trigger a divide-by-zero panic during probe, with a separate width underflow causing incorrect userspace reporting, but the practical impact is device-specific denial of service rather than memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64275 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64275 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: LOW 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-2026-64275 LOW CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-369;CWE-191;*CWE-20;Other CVSS 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'The Elan I2C touchpad driver could divide by zero during device probe when the device firmware or platform data reports zero x_traces or y_traces values. This can cause a kernel panic during probe and results in denial of service for systems using the affected device or malformed device parameters. A related arithmetic underflow in touch reporting could produce very large width values to userspace when the calculated width is smaller than ETP_FWIDTH_REDUCE. For the CVSS the PR:L is used for the paranoid score because a local user context with delegated device management or firmware update capability may be able to influence device state, while the base hardware oriented case is better represented as physical access. The issue is not network reachable and there is no evidence of memory corruption or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) YES OOB DANGER USB HARDWARE LINUS PACKET DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=1 ## 1. ActionableScore * Conservative score: 1 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate / Low-like**:: ## 2. Signal breakdown Conservative signals: * Firmware-mediated external influence: +1. Invalid values can come from device firmware or platform data. * Reliable kernel crash / strong DoS: +1. Zero x_traces or y_traces can cause division by zero during probe and kernel panic. * Physical-only or device-specific condition: -2. The main trigger depends on a specific Elan I2C touchpad path and malformed firmware or platform configuration. * Availability impact realistic: +1. Probe-time panic can affect the whole system on affected hardware. Conservative total: 1. Paranoid adjustment: * Paranoid score keeps the DoS signals but treats firmware or device-tree influence as somewhat more actionable in managed fleets or recovery scenarios. * No memory corruption, UAF, OOB write, page-cache corruption, object lifetime bug, or privilege escalation primitive is shown. Paranoid total: 2. ## 3. Reachability analysis The bug is triggered during Elan I2C touchpad probing or touch reporting when firmware, device tree, or platform properties provide invalid dimensions or trace counts. A normal remote attacker cannot reach this path. A normal local unprivileged user usually cannot modify firmware or device-tree data, so this is not a generic local attack surface. Namespaces and containers do not materially lower the privilege requirement because the affected path is hardware and platform-data driven. The affected driver is common on some laptops and Chromebooks, but the vulnerable condition requires malformed device parameters or firmware behavior. Call-site confidence: high, because the patch shows both the probe-time division path and the touch-reporting underflow path. ## 4. Severity interpretation This behaves like an ordinary Moderate or Low-like kernel robustness issue, not an Important-class vulnerability. The demonstrated impact is denial of service through a kernel panic during device probe. The arithmetic underflow can report a very large width value to userspace, but it does not show kernel memory corruption or a security boundary bypass. Theoretical exploitation beyond DoS is not supported by the patch. There is no evidence of attacker-controlled memory overwrite, stale pointer reuse, type confusion, refcount misuse, information disclosure, or privilege escalation. ## 5. One-sentence report phrase Malformed Elan I2C touchpad firmware or platform parameters can trigger a divide-by-zero panic during probe, with a separate width underflow causing incorrect userspace reporting, but the practical impact is device-specific denial of service rather than memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED. This is a validation and clamping fix for firmware or platform supplied numeric parameters, with DoS-only impact and no concrete memory-corruption or privilege-escalation primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: Input: elan_i2c - prevent division by zero and arithmetic underflow Commit: 59d4cc5e7a9785e4bdc9c55273274c6b49d4b58d Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=59d4cc5e7a9785e4bdc9c55273274c6b49d4b58d Commit description: The Elan I2C touchpad driver queries the device for its physical dimensions and trace counts to calculate the device resolution and width. However, if the device firmware or device tree provides invalid zero values for x_traces or y_traces, it results in a fatal division-by-zero exception leading to a kernel panic during device probe. Add checks to ensure these parameters are non-zero before performing the division. If invalid trace values are detected, fall back to a safe default of 1. Additionally, prevent an arithmetic underflow in the touch reporting logic. Previously, if the calculated or fallback width was smaller than ETP_FWIDTH_REDUCE (90), the subtraction would underflow, resulting in a massive unsigned integer being reported to userspace. Clamp the adjusted width to a minimum of 0 to safely handle small physical dimensions and fallback scenarios. Completing the probe with safe fallback values ensures the sysfs nodes are created, keeping the firmware update path intact so a recovery firmware can be flashed to the device. Fixes: 6696777 ("Input: add driver for Elan I2C/SMbus touchpad") Fixes: e3a9a12 ("Input: elan_i2c - do not query the info if they are provided") Signed-off-by: Ranjan Kumar Link: https://patch.msgid.link/20260612060339.3829666-1-kumarranja@chromium.org Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman Changed files: drivers/input/mouse/elan_i2c_core.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=59d4cc5e7a9785e4bdc9c55273274c6b49d4b58d ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64275 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64275 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:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/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: 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: LOW KPANIC detected for this report: NO Published priority for this report (same as in Subject): LOW 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).