Missing Cryptographic Step 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.
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Test your applications- Snyk IDSNYK-DOTNET-BOUNCYCASTLECRYPTOGRAPHY-20537012
- published6 Oct 2026
- disclosed2 Oct 2026
Introduced: 2 Oct 2026
NewCVE-2026-16000 (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 Missing Cryptographic Step in crypto/src/crypto/modes/KCcmBlockCipher.cs is vulnerable to ciphertext forgery due to missing nonce binding in DSTU 7624 CCM mode. An attacker can forge a valid ciphertext and authentication tag by observing or choosing messages encrypted without associated data and then combining outputs from multiple empty-AAD encryptions across different nonces. When ProcessAAD is skipped for empty associated text, the G1 block that mixes the nonce, message length, and MAC-size flag into the CBC-MAC is never processed, so the tag depends only on the plaintext. This breaks AEAD authenticity for applications that use KCcmBlockCipher directly with no associated data, letting a chosen-plaintext attacker produce cross-nonce forgeries that decrypt successfully under an unqueried nonce.