CVE-2026-16000
HIGH
MEDIUM
Priority: 0.02
BB Relevance:
77/100
Published: 2026-10-02
Modified: 2026-10-27
First seen: 2026-10-29
Status: active
Attack Surface
Network
Low Complexity
No Auth
No Interaction
Integ. Impact
CVSS Vector Breakdown
AV:
Network
AC:
Low
PR:
None
UI:
None
S:
X
AT:
None
VC:
None
VI:
High
VA:
None
Description
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.
Weakness Classification (1)
Affected Software (1)
| Vendor | Product | Version |
|---|---|---|
| bouncycastle | bc-csharp | < 2.7.0 |
References & Advisories (2)
Patch
Vendor Advisory
Patch