CVE-2026-16001
HIGH
8,2
Source: 91579145-5d7b-4cc5-b925-a0262ff19630
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A
Description
AI Translation Available
Exposure of the message authentication key through the encryption keystream in the stream mode of IesEngine (an IesEngine constructed without a block cipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker who has observed one encrypted message with known plaintext to forge shorter messages of their choosing that the recipient accepts as authentic, via a crafted ciphertext and MAC tag, because the MAC key was taken from the key derivation output directly after a keystream as long as the message, while the derivation input depends only on the static key pair and fixed parameters. The keystream revealed by that one message therefore contains the MAC key for every sufficiently shorter message.
354
Improper Validation of Integrity Check Value
DraftCommon Consequences
Security Scopes Affected:
Integrity
Other
Non-Repudiation
Potential Impacts:
Modify Application Data
Other
Hide Activities
Applicable Platforms
All platforms may be affected
https://github.com/bcgit/bc-csharp/commit/f881400b761134160ec2a05fd27c3e5694537…
https://github.com/bcgit/bc-csharp/wiki/CVE-2026-16001