CVE-2018-9424 is a high severity out-of-bounds write caused by a missing bounds check in the media framework crypto plugin (CryptoPlugin::decrypt in CryptoPlugin.cpp). NVD scores it 7.8. Google fixes it at security patch level 2018-07-01 or later. Install the device update that reaches that level.
What's affected
- Product: Android, in the media framework crypto plugin (CryptoPlugin::decrypt in CryptoPlugin.cpp).
- Releases listed by the bulletin: 8.0 and 8.1. The NVD product list shows only some Android releases, so treat the bulletin as the fuller list.
- Fixed in: security patch level 2018-07-01 or later, according to the Android Security Bulletin for July 2018.
- Impact in the record: local escalation of privilege with no extra privileges and no user interaction.
- Severity: NVD scores it 7.8 High (vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). The bulletin lists it as High, type EoP. The two ratings agree.
- Weakness classes: CWE-787 (Out-of-bounds Write).
How to check if you're exposed
- On the device, open Settings and find the Android security patch level, usually under About phone. The exact path varies by manufacturer. A date earlier than 2018-07-01 means the fix is not present.
- With a USB debugging connection, run
adb shell getprop ro.build.version.security_patch. It prints the patch level as a date. You need 2018-07-01 or later. - For a fleet, export the patch level from your mobile device management console and filter for dates earlier than 2018-07-01.
- Match each device against the release list above. Devices on releases outside it are not named for this CVE, but check them against the other entries in the same bulletin.
What to do now
- Identify every Android device in scope and record its current security patch level.
- Roll out the manufacturer or carrier update that reaches 2018-07-01 or later. Google publishes the fixes, but each device maker decides when its devices receive them.
- For devices that no longer receive updates, plan replacement or limit what they can reach, such as corporate mail and internal apps.
- Write the update policy down, with a maximum patch age, and report exceptions.
Why it matters
Only Android 8.0 and 8.1 are listed, in both the NVD record and the bulletin. Devices on older releases are not named for this specific entry, and devices on later releases were expected to ship with the fix.
The decrypt function sits in the media framework and works on buffers it is handed. A missing bounds check on that path allows a write beyond the destination buffer. Corrupting the memory of a privileged media process is what the record means by escalation of privilege. The record's KEV flag is false, so CISA does not list it as exploited. The bulletin says Google had no reports of active customer exploitation or abuse of the newly reported issues in it. That is the absence of a report in the sources read, not proof that no one has tried.
Quick check
Does this affect Android 7?
The NVD record and the July bulletin list Android 8.0 and 8.1 for this CVE. Other issues in the same bulletin cover older releases, so check each one rather than assuming.
Which patch level should I look for?
The Android Security Bulletin for July 2018 places this fix at 2018-07-01. Any date at or after 2018-07-01 includes it. Some makers ship it under a different update name, so check the date.
Sources
- Android Security Bulletin for July 2018: Affected releases, severity, type and the patch level that carries the fix.
Last reviewed: 19 October 2026.
