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AndroidOperating system · Google

CVE-2018-9400

MEDIUM · 6.7 CVSS v3.1 Published 2024-12-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In gt1x_debug_write_proc and gt1x_tool_write of drivers/input/touchscreen/mediatek/GT1151/gt1x_generic.c and gt1x_tools.c, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a kernel-level vulnerability in the MediaTek GT1151 touchscreen driver (gt1x_generic.c and gt1x_tools.c). The functions gt1x_debug_write_proc and gt1x_tool_write lack proper bounds checking before performing write operations, allowing an attacker with System privileges to write beyond allocated buffer boundaries and escalate to root.

MitigationApply the vendor-supplied kernel/firmware patch that adds bounds validation to the write operations in the affected touchscreen driver functions. For end-users, apply security updates provided by the device OEM.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AndroidOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm device uses MediaTek chipset with GT1151 touchscreen
    Check /sys/class/input/input*/name or /proc/bus/input/devices for GT1151 or 'gt1x' touchscreen driver
    Affected if The device does not list GT1151 or gt1x as the touchscreen controller - if not present, the vulnerability does not apply
  2. Identify kernel source containing gt1x driver
    Search /proc/version or uname -a for kernel version, then locate gt1x_generic.c and gt1x_tools.c in the kernel source tree
    Affected if The gt1x driver source files are not present in the running kernel - vulnerability only applies if this specific driver is in use
  3. Verify vulnerable functions exist in driver
    grep for 'gt1x_debug_write_proc' and 'gt1x_tool_write' in the compiled driver binary or source
    Affected if These exact function names are found without bounds checking logic - their presence indicates the vulnerability exists
  4. Check if driver is loaded as kernel module
    lsmod | grep gt1x or check /sys/module/ for gt1x module presence
    Affected if The gt1x touchscreen driver module is loaded and active on the device
  5. Confirm System-level access is possible
    Verify the device allows apps to obtain System privilege (adb shell pm list permissions or check SELinux context)
    Affected if An attacker can obtain System privileges - exploitation requires this privilege level to trigger the buffer overflow

The device is affected only if it uses a MediaTek chipset with the GT1151 touchscreen driver containing the vulnerable gt1x_debug_write_proc and gt1x_tool_write functions, and an attacker can obtain System-level access.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-supplied kernel/firmware patch that adds bounds validation to the write operations in the affected touchscreen driver functions. For end-users, apply security updates provided by the device OEM.

Recommended fix Moderate confidence

Android Security Patch Level November 2018 or later (Android 9.0 Pie or later recommended)

  1. Identify the current Android Security Patch Level on the device via Settings > About Phone > Build Number
  2. Update the device to the latest available Android system update that includes the Android Security Patch Level for November 2018 or later
  3. For enterprise/embedded devices using the MediaTek GT1151 touchscreen driver, obtain and apply the updated firmware from the device OEM or MediaTek that contains the bounds check fix in gt1x_debug_write_proc and gt1x_tool_write functions
  4. Verify the fix was applied by confirming the kernel driver version or checking the Android Security Patch Level shows November 2018 or later in Settings > About Phone > Security Patch Level
Caveat Major Android version upgrades (e.g., from Android 8 to 9) may introduce compatibility issues with legacy applications; test thoroughly before deploying in production environments

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Android Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
21.0 hours of engineering $3,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-9400 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data