Improper verification of cryptographic signature in the attribute certificate path validator (PkixAttrCertPathValidator, also used by PkixAttrCertPathBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker to have a forged X.509 attribute certificate accepted as valid, and so obtain whatever roles or privileges an application grants on the strength of its attributes, via an attribute certificate that names a trusted attribute authority as its issuer but was not signed by it, because the RFC 3281 validation steps check the holder and issuer certification paths, validity period, extensions and revocation status but never verify the attribute certificate's signature with the issuer's public key. Only applications that use these classes to validate attribute certificates are affected.
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Affected Vendors & Products
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History
Wed, 28 Oct 2026 13:30:00 +0000
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Bouncycastle
Bouncycastle bc-csharp |
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| CPEs | cpe:2.3:a:bouncycastle:bc-csharp:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Bouncycastle
Bouncycastle bc-csharp |
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cvssV3_1
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Sun, 04 Oct 2026 22:15:00 +0000
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Legion Of The Bouncy Castle Inc.
Legion Of The Bouncy Castle Inc. bc-csharp |
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| Vendors & Products |
Legion Of The Bouncy Castle Inc.
Legion Of The Bouncy Castle Inc. bc-csharp |
Fri, 02 Oct 2026 20:30:00 +0000
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ssvc
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Fri, 02 Oct 2026 07:30:00 +0000
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| Description | Improper verification of cryptographic signature in the attribute certificate path validator (PkixAttrCertPathValidator, also used by PkixAttrCertPathBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker to have a forged X.509 attribute certificate accepted as valid, and so obtain whatever roles or privileges an application grants on the strength of its attributes, via an attribute certificate that names a trusted attribute authority as its issuer but was not signed by it, because the RFC 3281 validation steps check the holder and issuer certification paths, validity period, extensions and revocation status but never verify the attribute certificate's signature with the issuer's public key. Only applications that use these classes to validate attribute certificates are affected. | |
| Title | Attribute certificate path validation does not verify the attribute certificate's signature | |
| Weaknesses | CWE-347 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: bcorg
Published: 2026-10-02T07:04:17.323Z
Updated: 2026-10-02T19:16:19.996Z
Reserved: 2026-07-16T23:50:45.118Z
Link: CVE-2026-63571
Updated: 2026-10-02T19:15:56.903Z
Status : Analyzed
Published: 2026-10-02T08:17:01.993
Modified: 2026-10-28T13:19:23.467
Link: CVE-2026-63571
No data.