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AndroidOperating system · Google

CVE-2018-9407

MEDIUM · 5.5 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 →
57/100
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 emmc_rpmb_ioctl of emmc_rpmb.c, there is an Information Disclosure due to a Missing Bounds Check. This could lead to Information Disclosure of kernel data.

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

This is an information disclosure vulnerability in the Linux kernel's eMMC RPMB (Replay Protected Memory Block) driver. The emmc_rpmb_ioctl function lacks proper bounds checking, allowing an attacker to read beyond intended memory boundaries and leak kernel data. RPMB is a secure partition in eMMC storage used for sensitive operations like secure key storage.

MitigationApply the kernel patch that adds proper bounds checking to the emmc_rpmb_ioctl function to validate all buffer sizes before accessing memory. This is a kernel-level fix requiring recompilation and deployment of the patched kernel.

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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 RPMB driver is present in the kernel
    Check if the kernel configuration includes MMC_RPMB support: look for 'CONFIG_MMC_RPMB=y' in /boot/config-* or /proc/config.gz, or check /sys/class/mmc_rpmb exists
    Affected if CONFIG_MMC_RPMB is enabled or /sys/class/mmc_rpmb directory exists, indicating the RPMB driver is compiled into the kernel
  2. Identify RPMB device node availability
    Check for RPMB device files: ls -la /dev/block/rpmb* or ls -la /dev/rpmb*
    Affected if RPMB device nodes exist (e.g., /dev/block/rpmb0), meaning the secure partition is exposed to userspace
  3. Confirm RPMB ioctl interface is accessible
    Attempt to access the RPMB driver ioctl interface via the device node or check driver source for emmc_rpmb_ioctl function presence in /proc/kallsyms or System.map
    Affected if The emmc_rpmb_ioctl symbol is present in the kernel, indicating the vulnerable function exists
  4. Determine if RPMB is actively used on the device
    Check if any process or service is accessing RPMB devices (e.g., look for mmc_rpmb usage in /proc/*/fd or check for RPMB-related daemons), or examine if RPMB partitions are mounted
    Affected if Any userspace process or service is actively using the RPMB interface, exposing the vulnerable code path

Any Android device with the eMMC RPMB driver enabled and the RPMB device node exposed to userspace is affected by this vulnerability, regardless of kernel version since all Android versions are impacted.

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 kernel patch that adds proper bounds checking to the emmc_rpmb_ioctl function to validate all buffer sizes before accessing memory. This is a kernel-level fix requiring recompilation and deployment of the patched kernel.

Recommended fix Moderate confidence

Android devices with 2018-12-01 security patch level or later (Android 9 Pie, Android 8.x, or Android 7.x with December 2018 security update)

  1. Check your current Android version in Settings > About Phone
  2. Identify your device's carrier or manufacturer to get specific update information
  3. Navigate to Settings > System > Software Update (or Settings > About Phone > System Updates)
  4. Check for and install the latest available security update
  5. If no update is available, contact your device manufacturer or carrier for patch availability timeline
  6. Alternatively, consider upgrading to a newer Android version (Android 9 or later) that includes the December 2018 security patch level
Caveat Some devices may no longer receive security updates if they are beyond the manufacturer's support window; upgrading to a newer Android version may reset app data or require reconfiguration

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

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,500
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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-2018-9407 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