Status: UPDATED
| Advisory ID: CVE-2026-63567
Key Details
| CVE | CVE-2026-63567 |
| CVSS Score / Version | 8.2 (High) / CVSS v4.0 |
| Updated | 2026-10-02 |
| Affected products | Legion of the Bouncy Castle Inc. bc-csharp |
| Classified as | CWE-203 (Observable Discrepancy) |
Affected Products, Subsystems & Sectors
| Subsystems | General OT |
| Sectors | Multiple |
What to Know
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 padding-oracle attack, because in block-cipher mode the engine decrypts the ciphertext and removes its padding before verifying the MAC. A padding failure is therefore reported with a different error message, and without the MAC computation, compared with a MAC failure. Only applications that construct IesEngine directly with a padded block cipher, such as AES in CBC mode with PKCS#7 padding, are affected; stream-mode IES is not. (NVD)
What to Do
Monitor Legion of the Bouncy Castle Inc.'s web page for any future patch releases.
References