In the Bouncy Castle JCE Provider version 1.55 and earlier the DSA key pair generator generates a weak private key if used with default values. If the JCA key pair generator is not explicitly initialised with DSA parameters, 1.55 and earlier generates a private value assuming a 1024 bit key size. In earlier releases this can be dealt with by explicitly passing parameters to the key pair generator.
BouncyCastle TLS prior to version 1.0.3, when configured to use the JCE (Java Cryptography Extension) for cryptographic functions, provides a weak Bleichenbacher oracle when any TLS cipher suite using RSA key exchange is negotiated. An attacker can recover the private key from a vulnerable application. This vulnerability is referred to as "ROBOT."
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.