Improper Validation of Integrity Check Value Affecting bouncycastle.cryptography package, versions [,2.7.0)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-DOTNET-BOUNCYCASTLECRYPTOGRAPHY-20537007
- published6 Oct 2026
- disclosed2 Oct 2026
Introduced: 2 Oct 2026
NewCVE-2026-15999 (opens in a new tab)How to fix?
Upgrade BouncyCastle.Cryptography to version 2.7.0 or higher.
Overview
Affected versions of this package are vulnerable to Improper Validation of Integrity Check Value through CcmParameters and CcmBlockCipher in the CMS ASN.1 parameter parsing and CCM cipher initialization paths. An attacker can modify AES-CCM-encrypted CMS content without detection by supplying an AlgorithmIdentifier whose CCM parameters declare a zero or otherwise invalid aes-ICVlen, causing decryption to compare an empty or too-short tag. This affects callers such as ParameterUtilities.GetCipherParameters, including CmsEnvelopedData and CmsEnvelopedDataParser when processing EnvelopedData encrypted with AES-CCM, and any code that initializes CcmBlockCipher for decryption with an unchecked tag length.