CVE-2016-2427

DISPUTED The AES-GCM specification in RFC 5084, as used in Android
5.x and 6.x, recommends 12 octets for the aes-ICVlen parameter field, which
might make it easier for attackers to defeat a cryptographic protection
mechanism and discover an authentication key via a crafted application, aka
internal bug 26234568. NOTE: The vendor disputes the existence of this
potential issue in Android, stating “This CVE was raised in error: it
referred to the authentication tag size in GCM, whose default according to
ASN.1 encoding (12 bytes) can lead to vulnerabilities. After careful
consideration, it was decided that the insecure default value of 12 bytes
was a default only for the encoding and not default anywhere else in
Android, and hence no vulnerability existed.”

Notes