CVE-2026-15999High· 8.2▾ TwilightImproper validation of integrity check value in the AES-CCM implementation (CcmParameters and CcmBlockCipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to modify CCM-encrypted content without d…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 45.1 · likelihood 0.1 · 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% → 0.3%
Improper validation of integrity check value in the AES-CCM implementation (CcmParameters and CcmBlockCipher) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an on-path attacker to modify CCM-encrypted content without detection via an AlgorithmIdentifier whose CCMParameters declare an authentication tag (aes-ICVlen) of zero or another length outside the RFC 5084 set, because CcmParameters accepted any value and CcmBlockCipher validated the tag length only when encrypting, so decryption compared a zero-length or very short tag. Affected paths include ParameterUtilities.GetCipherParameters, used by CmsEnvelopedData and CmsEnvelopedDataParser for EnvelopedData encrypted with AES-CCM, and any caller passing an unchecked tag length to CcmBlockCipher for decryption.
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-2026-16001High· 8.2Exposure 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
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
CVE-2026-63571High· 8.7Improper verification of cryptographic signature in the attribute certificate path validator (PkixAttrCertPathValidator, also used by PkixAttrCertPathBuilder) in Legion of the Bouncy Castle Inc