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AndroidOperating system · Google

CVE-2018-9391

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 update_gps_sv and output_vzw_debug of vendor/mediatek/proprietary/hardware/connectivity/gps/gps_hal/src/gpshal_wor ker.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

An out-of-bounds write vulnerability exists in the MediaTek GPS hardware abstraction layer (HAL) in the update_gps_sv and output_vzw_debug functions within gpshal_worker.c. The vulnerability stems from missing bounds checks before writing data, allowing a local attacker with System-level privileges to escalate to root through a memory corruption vulnerability.

MitigationApply the MediaTek patch for CVE-2018-9391 which adds proper bounds validation in the gpshal_worker.c file. Users should update device firmware from OEM or MediaTek-provided sources containing the security fix.

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. Verify MediaTek chipset is present
    Check /proc/cpuinfo for 'MediaTek' or check build.prop for mtk platform. Run: cat /proc/cpuinfo | grep -i media or getprop | grep -i mtk
    Affected if Device does not have a MediaTek chipset - the vulnerability only affects MediaTek hardware, not other vendors like Qualcomm or Samsung Exynos
  2. Locate the MediaTek GPS HAL library
    Search for MediaTek GPS library files. Run: find /system -name '*gps*mtk*' or ls -la /system/lib/hw/gps.mtk.so 2>/dev/null
    Affected if No MediaTek GPS library found - device may use a different GPS implementation not affected by this specific flaw
  3. Check GPS HAL version or build info
    Examine the library for version strings or metadata. Run: strings /system/lib/hw/gps.mtk.so | grep -i version or check /vendor/etc/gps.conf for build identifiers
    Affected if Unable to determine version - version information may be needed to compare against fixed releases; contact OEM for specific fixed build numbers
  4. Verify vulnerable functions exist in binary
    Check for vulnerable function names in the binary. Run: strings /system/lib/hw/gps.mtk.so | grep -E 'update_gps_sv|output_vzw_debug'
    Affected if Functions not present - the specific vulnerable code paths may have been refactored; however their absence does not guarantee the fix was applied
  5. Confirm System-level access exists for exploitation context
    This vulnerability requires System-level (not root) privileges to exploit. Check current privilege level: whoami or id command output
    Affected if Running as unprivileged user - the attack requires System-level access first; however the vulnerability still exists in the HAL regardless of current user context

A device is affected if it uses a MediaTek chipset with a GPS HAL that contains the vulnerable update_gps_sv or output_vzw_debug functions without the bounds validation fix - contact the device OEM to confirm if the security patch for CVE-2018-9391 has been applied.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the MediaTek patch for CVE-2018-9391 which adds proper bounds validation in the gpshal_worker.c file. Users should update device firmware from OEM or MediaTek-provided sources containing the security fix.

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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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-2018-9391 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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