CVE-2026-12803 KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery)

In Bouncy Castle for Java before 1.85, KCCMBlockCipher MAC does not bind nonce when AAD is absent cross-nonce AEAD forgery. This issue also affects Bouncy Castle for Java LTS before 2.73.12...

PT-2026-67016

Name of the Vulnerable Software and Affected Versions Bouncy Castle for Java versions prior to 1.85 Bouncy Castle for Java LTS versions prior to 2.73.12 Description The KCCMBlockCipher MAC does not bind the nonce when Additional Authenticated Data AAD is absent, which allows for cross-nonce AEAD...