CVE-2016-2419

Vulnerability

In media/libmedia/IDrm.cpp of mediaserver in Android 6.x before the 2016-04-01 security update, a key-request data structure is not properly initialized. When a DRM (Digital Rights Management) provisioning request is made, the uninitialized memory can contain leftover data from previous operations. The vulnerability, identified as internal bug 26323455, affects Android versions 6.0 and 6.0.1. The fix was committed in commit 5a856f2092f7086aa0fea9ae06b9255befcdcd34 [2].

Exploitation

An attacker can trigger the vulnerability by sending a crafted DRM provisioning request to the mediaserver process. No authentication is required, as the affected interface is exposed to third-party applications. The attacker does not need any special permissions; any application can invoke the vulnerable code path. By providing a specific key request type that causes the uninitialized memory to be returned, the attacker can read arbitrary portions of process memory [1][2].

Impact

Successful exploitation allows an attacker to leak sensitive information from the mediaserver process memory, including cryptographic keys, credentials, or other protected data. This information disclosure can be leveraged to obtain Signature or SignatureOrSystem-level permissions, effectively bypassing Android's security model and gaining elevated privileges. The CVSS v3 score is 9.8 (Critical), reflecting the high confidentiality impact and potential for full system compromise [1].

Mitigation

Google released a fix in the April 2016 Nexus Security Bulletin. All Android 6.x devices should apply the update dated 2016-04-01 or later. Users can install the update via the device's system update mechanism or by flashing a new factory image. There is no known workaround; the vulnerability is entirely eliminated by the patch that properly initializes the data structure [1][2].