Executive brief
AWS S3 Encryption Clients, which are used to encrypt data before it is uploaded to cloud storage, are vulnerable to a cryptographic flaw. This issue allows an attacker to replace the encrypted data key with a different one if the key is stored in a separate instruction file. This could potentially lead to data integrity issues or unauthorized access to encrypted records.
Technical details
The AWS S3 Encryption Clients (S3EC) fail to implement key commitment when the encrypted data key (EDK) is stored in an 'Instruction File' rather than the S3 metadata record. This vulnerability class, known as an 'Invisible Salamanders' attack, occurs because the EDK is not cryptographically bound to the ciphertext. An attacker with the ability to modify the instruction file could replace the EDK, potentially leading to a loss of cryptographic integrity. AWS is addressing this by introducing key commitment to bind the EDK to the ciphertext, requiring updates to both a minor version for compatibility and a major version for full enforcement.
Affected products
- AWS S3 Encryption Client for Java <= 3.5.0
- AWS S3 Encryption Client for Go <= 3.1.0
- AWS S3 Encryption Client for .NET <= 3.1
- AWS AWS SDK for C++ <= 1.11.711
- AWS AWS SDK for PHP <= 3.367.0
- AWS AWS SDK for Ruby <= 1.207.0
CVE identifiers
- CVE-2025-14763
- CVE-2025-14759
- CVE-2025-14762
- CVE-2025-14760
- CVE-2025-14761
- CVE-2025-14764
Timeline
- 2025-12-17: disclosed
- 2025-12-17: advisory