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AndroidOperating system · Google

CVE-2018-9396

MEDIUM · 6.7 CVSS v3.1 Published 2024-12-04
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 rpc_msg_handler and related handlers of drivers/misc/mediatek/eccci/port_rpc.c, there is a possible out of bounds write due to an incorrect 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 · moderate confidence

An out-of-bounds write vulnerability exists in the RPC message handling functions (rpc_msg_handler and related handlers) in Mediatek's ECCCI driver (port_rpc.c) due to incorrect bounds checking. This memory corruption issue allows local privilege escalation from System privileges, requiring no user interaction.

MitigationApply the Mediatek vendor patch to fix the bounds checking in port_rpc.c; until then, restrict System-level access and monitor for exploit attempts targeting this driver.

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. Identify if device uses a Mediatek chipset
    Check /proc/cpuinfo for 'MediaTek' or run 'lspci' (if available) to see the SoC. Alternatively, check /sys/firmware/devicetree/base/compatible for Mediatek strings.
    Affected if The device does not have a Mediatek chipset - the ECCCI driver is Mediatek-specific and this CVE only applies to Mediatek-based Android devices.
  2. Locate the ECCCI driver module
    Search for the eccci kernel module: 'find /lib/modules -name "*eccci*"' or 'find /system/lib/modules -name "*eccci*"'. Also search for port_rpc: 'find / -name "*port_rpc*"' 2>/dev/null.
    Affected if The eccci driver module or port_rpc component is not found on the device - the vulnerability only exists where this specific driver is present.
  3. Check if the ECCCI driver is loaded
    Run 'lsmod | grep -i eccci' or check /proc/modules for 'eccci'. Also check /sys/module/eccci exists using 'ls /sys/module/'.
    Affected if The ECCCI driver module is not loaded and the module file does not exist - the vulnerability cannot be exploited if the driver is not present.
  4. Verify RPC message handling is active
    Check for RPC-related device nodes or debug interfaces: 'ls -la /dev/*rpc*' and review kernel logs with 'dmesg | grep -i rpc' or 'logcat | grep -i eccci'.
    Affected if RPC message handling through the ECCCI driver is not active - exploitation requires the RPC handler functions to be invoked.

A user is affected if their Mediatek-based Android device has the ECCCI driver present with RPC message handling enabled, as this is where the bounds checking flaw in port_rpc.c can be exploited for privilege escalation.

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 Mediatek vendor patch to fix the bounds checking in port_rpc.c; until then, restrict System-level access and monitor for exploit attempts targeting this driver.

Recommended fix High confidence

Android Security Patch Level 2018-08-01 or later (vendor-specific patch required)

  1. 1. Check the Android Security Patch Level on the device to determine current update status
  2. 2. Obtain the vendor-specific patch for CVE-2018-9396 from the device manufacturer or carrier
  3. 3. Apply the patch through the device's standard system update mechanism
  4. 4. Verify the patch was applied by checking Settings > About Phone > Security Patch Level reflects the August 2018 security update or later
  5. 5. Alternatively, if using a custom ROM or AOSP build, apply the upstream kernel fix which corrects the bounds check in drivers/misc/mediatek/eccci/port_rpc.c to prevent the out-of-bounds write
Caveat Patch availability varies by device manufacturer and carrier; many older devices may not receive this specific patch

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

Fix this in Android Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2018-9396 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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