A weak robustness vulnerability exists in the AWS Encryption SDKs due to the non-committing property of AES-GCM and other AEAD ciphers. This allows an attacker to craft a unique ciphertext that decrypts to multiple different results, particularly in a multi-recipient setting. The vulnerability also enables information leakage and ciphertext forgery attacks. An attacker can create ciphertexts that leak the user's AWS account ID, encryption context, user agent, and IP address upon decryption. Additionally, an attacker can create ciphertexts that are accepted by other users. The non-committing property of AES-GCM can cause nonidentical plaintexts when decrypting a single ciphertext with two different keys.