CVE-2026-63567

Observable discrepancy in IesEngine.DecryptBlock in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has captured an IES or ECIES ciphertext, and who can submit modified ciphertexts for decryption under the same key pair, to recover its plaintext via a CBC...

CVE-2026-63567

The bc-csharp library by Bouncy Castle Inc. is vulnerable in versions before 2.7.0 due to an observable discrepancy in IesEngine.DecryptBlock. In block-cipher mode, the engine decrypts the ciphertext and removes padding before verifying the MAC. This allows a remote attacker to perform a CBC padd...

CVE-2026-63567 IesEngine block-cipher mode checks padding before MAC (CBC padding oracle)

Observable discrepancy in IesEngine.DecryptBlock in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has captured an IES or ECIES ciphertext, and who can submit modified ciphertexts for decryption under the same key pair, to recover its plaintext via a CBC...

EUVD-2026-91218

Observable discrepancy in IesEngine.DecryptBlock in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has captured an IES or ECIES ciphertext, and who can submit modified ciphertexts for decryption under the same key pair, to recover its plaintext via a CBC...

PT-2026-104105

Observable discrepancy in IesEngine.DecryptBlock in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has captured an IES or ECIES ciphertext, and who can submit modified ciphertexts for decryption under the same key pair, to recover its plaintext via a CBC...