CVE-2018-9433 is a high severity type confusion caused by improper input validation in the V8 JavaScript engine array built-ins (ArrayConcatVisitor in builtins-array.cc). NVD scores it 8.8. 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 V8 JavaScript engine array built-ins (ArrayConcatVisitor in builtins-array.cc).
- Releases listed by the bulletin: 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2. 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: remote code execution with no privileges, user interaction needed.
- Severity: NVD scores it 8.8 High (vector AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). The bulletin lists it as Critical, type RCE. Both ratings are given because they differ.
- Weakness classes: CWE-116 (Improper Encoding or Escaping of Output).
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
In this case the bulletin is stricter than NVD. Google rates it Critical, NVD scores it 8.8 High. The framework section of the bulletin lists Android 6.0 through 7.1.2. User interaction is needed, in the usual sense that a user has to open or view content.
Type confusion means code treats an object as one type when it is another, so field offsets and sizes are read wrongly. JavaScript engines are prone to it because they optimise aggressively around type assumptions. NVD tags this CVE as an improper encoding or escaping weakness, which does not describe type confusion directly, so the description text is the better guide. 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
Which severity do I report to my board?
Report the higher bulletin rating of Critical alongside the NVD score of 8.8 High, and explain that user interaction is needed. Showing both is more honest than picking one.
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.
