Vulnerability Details 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 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.005
EPSS Ranking 39.4%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2026-63567
-
cpe:2.3:a:bouncycastle:bc-csharp:-
-
cpe:2.3:a:bouncycastle:bc-csharp:1.7.0
-
cpe:2.3:a:bouncycastle:bc-csharp:1.7.0.1
-
cpe:2.3:a:bouncycastle:bc-csharp:1.7.0.2
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.0
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.1
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.10
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.2
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.3
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.4
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.5
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.6
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.7
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.8
-
cpe:2.3:a:bouncycastle:bc-csharp:1.8.9
-
cpe:2.3:a:bouncycastle:bc-csharp:1.9.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.0.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.1.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.1.1
-
cpe:2.3:a:bouncycastle:bc-csharp:2.2.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.2.1
-
cpe:2.3:a:bouncycastle:bc-csharp:2.3.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.3.1
-
cpe:2.3:a:bouncycastle:bc-csharp:2.4.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.5.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.5.1
-
cpe:2.3:a:bouncycastle:bc-csharp:2.6.0
-
cpe:2.3:a:bouncycastle:bc-csharp:2.6.1
-
cpe:2.3:a:bouncycastle:bc-csharp:2.6.2