CVE-2026-47842: Deterministic AES/CBC Encryption in Spring Security AesBytesEncryptor Allows Ciphertext Correlation
Applications using AesBytesEncryptor with the two-argument constructor or when passing a null IV generator and CBC as the encryption mode encrypt data with AES/CBC using a null (all-zero) initialization vector. Spring Security 7.1.0 Spring Security 7.0.0 - 7.0.6 Spring Security 6.5.0 - 6.5.11 Spring Security 6.4.0 - 6.4.18 Spring Security 5.8.0 - 5.8.27 Spring Security 5.7.0 - 5.7.25
Affected Software
Event History
Frequently Asked Questions
Which applications are affected?
Applications are affected if they use Spring Security's AesBytesEncryptor with the two-argument constructor, or pass a null IV generator while using CBC mode. The listed affected releases include Spring Security 7.1.0, 7.0.0 through 7.0.6, 6.5.0 through 6.5.11, 6.4.0 through 6.4.18, 5.8.0 through 5.8.27, and 5.7.0 through 5.7.25.
What does an attacker need to exploit this issue?
The issue is remotely exploitable with low attack complexity and requires low privileges; no user interaction is required. Exploitation relies on encryption being performed with the affected AesBytesEncryptor configuration, which uses an all-zero CBC initialization vector.
What is the security impact?
Using a fixed all-zero IV makes AES/CBC encryption deterministic, allowing ciphertext correlation. The provided severity vector indicates a high confidentiality impact, with no integrity or availability impact.