Improper Verification of Cryptographic Signature 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-20537008
- published6 Oct 2026
- disclosed2 Oct 2026
Introduced: 2 Oct 2026
NewCVE-2026-63571 (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 Verification of Cryptographic Signature in PkixAttrCertPathValidator and PkixAttrCertPathBuilder. An attacker can have a forged X.509 attribute certificate accepted as valid by supplying a certificate that names a trusted attribute authority as its issuer but is not actually signed by that authority. The validator checks the holder and issuer certification paths, validity period, extensions, and revocation status, but does not verify the attribute certificate’s signature with the issuer’s public key. Applications that rely on these classes for attribute certificate validation can then grant roles or privileges based on untrusted attributes.