CVE-2026-16000

Missing cryptographic step in the DSTU 7624 CCM mode implementation (KCcmBlockCipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can observe encrypted messages of known or chosen content to forge ciphertexts with valid authentication tags, via messages encrypted without associated data. The cause is that the G1 block, which binds the nonce, the message length and the parameter flags into the CBC-MAC, was processed only when associated data was present. Without associated data the tag was a CBC-MAC of the plaintext alone, independent of the nonce. Only applications that use KCcmBlockCipher directly and supply no associated data are affected.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/bcgit/bc-csharp/commit/b01e9e6c0e231b90867fbaf03bf148bde6f9ccfb	Patch
https://github.com/bcgit/bc-csharp/wiki/CVE-2026-16000	Patch Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:bouncycastle:bc-csharp:*:*:*:*:*:*:*:*

History

27 Oct 2026, 16:32

Type	Values Removed	Values Added
References	~~() https://github.com/bcgit/bc-csharp/commit/b01e9e6c0e231b90867fbaf03bf148bde6f9ccfb -~~	() https://github.com/bcgit/bc-csharp/commit/b01e9e6c0e231b90867fbaf03bf148bde6f9ccfb - Patch
References	~~() https://github.com/bcgit/bc-csharp/wiki/CVE-2026-16000 -~~	() https://github.com/bcgit/bc-csharp/wiki/CVE-2026-16000 - Patch, Vendor Advisory
First Time		Bouncycastle bc-csharp Bouncycastle
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
CPE		cpe:2.3:a:bouncycastle:bc-csharp::::::::

02 Oct 2026, 07:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-02 07:16

Updated : 2026-10-27 16:32

NVD link : CVE-2026-16000

Mitre link : CVE-2026-16000

CVE.ORG link : CVE-2026-16000

JSON object : View

Products Affected

bouncycastle

bc-csharp

CWE

CWE-325

Missing Cryptographic Step

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