Hello Google Play Developer,
We detected that your app(s) listed at the end of this email are using an unsafe version of the libpng library. Apps with vulnerabilities like this can expose users to risk of compromise and may be considered in violation of our Malicious Behavior policy.
What’s happening
Beginning September 17, 2016, Google Play will block publishing of any new apps or updates that use vulnerable versions of libpng. Your published APK version will not be affected, however any updates to the app will be blocked unless you address this vulnerability.
Action required: Migrate your app(s) to use libpng v1.0.66, v.1.2.56, v.1.4.19, v1.5.26 or higher as soon as possible and increment the version number of the upgraded APK.
Next steps
1. Download the latest version of libpng from the libpng website.
2. Sign in to your Developer Console and submit the updated version of your app.
3. Check back after five hours - we’ll show a warning message if the app hasn’t been updated correctly.
The vulnerability stems from an out of bounds memory access that could potentially lead to code execution. Versions 1.0.x before 1.0.66, 1.1.x and 1.2.x before 1.2.56, 1.3.x and 1.4.x before 1.4.19, and 1.5.x before 1.5.26 are affected.