CVEvulnerability
CVE-2026-15999
8.2 HIGH
Official page ↗
- Status
- Analyzed
- Published
- 2026-10-02
- Last modified
- 2026-10-27
- Assigner
- 91579145-5d7b-4cc5-b925-a0262ff19630
- CVSS 4.0 (91579145-5d7b-4cc5-b925-a0262ff19630)
- 8.2 HIGH — CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Weaknesses
- CWE-354
Description
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.
Affected configurations
• bouncycastle bc-csharp (< 2.7.0)
Related
Weakness · CWE (1)
- CWE-354 Improper Validation of Integrity Check Value weakness