CVE-2026-16001High· 8.2▾ TwilightExposure 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 atta…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 45.1 · likelihood 0 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Exploit-prediction probability, daily snapshots since Oct 2.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.2%
0.2% → 0.2%
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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-103601High· 8.2Release of unverified plaintext in the CCM (CcmBlockCipher) and DSTU 7624 CCM (KCcmBlockCipher) AEAD modes in Legion of the Bouncy Castle Inc
CVE-2026-15999High· 8.2Improper validation of integrity check value in the AES-CCM implementation (CcmParameters and CcmBlockCipher) in Legion of the Bouncy Castle Inc
CVE-2026-63567High· 8.2Observable discrepancy in IesEngine.DecryptBlock in Legion of the Bouncy Castle Inc
CVE-2026-71888High· 8.7In Bouncy Castle for Java before 1.86, the streaming CMS AuthenticatedData parser accepted a message whose digestAlgorithm and authAttrs fields disagreed about whether authenticated attributes were present
CVE-2026-85515High· 8.2In Bouncy Castle for Java before 1.86, a truncated OpenPGP encrypted message was accepted with no error reported, and on the SEIPD version 1 path with no integrity check performed at all
CVE-2026-63570High· 7.1Loop with unreachable exit condition in Pkcs12Store.GetCertificateChain in Legion of the Bouncy Castle Inc