{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63568", "assignerOrgId": "91579145-5d7b-4cc5-b925-a0262ff19630", "state": "PUBLISHED", "assignerShortName": "bcorg", "dateReserved": "2026-07-16T23:48:46.076Z", "datePublished": "2026-10-02T06:59:30.557Z", "dateUpdated": "2026-10-02T06:59:30.557Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "91579145-5d7b-4cc5-b925-a0262ff19630", "shortName": "bcorg", "dateUpdated": "2026-10-02T06:59:30.557Z"}, "title": "Unbounded CMP/CRMF password-based MAC iteration count allows CPU exhaustion", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-770", "description": "CWE-770 Allocation of Resources Without Limits or Throttling", "type": "CWE"}]}], "impacts": [{"descriptions": [{"lang": "en", "value": "Denial of Service (CPU exhaustion before the MAC is checked)"}]}], "affected": [{"vendor": "Legion of the Bouncy Castle Inc.", "product": "bc-csharp", "collectionURL": "https://www.nuget.org/packages/BouncyCastle.Cryptography", "packageName": "BouncyCastle.Cryptography", "repo": "https://github.com/bcgit/bc-csharp", "programFiles": ["crypto/src/crmf/PKMacBuilder.cs", "crypto/src/cmp/ProtectedPkiMessage.cs", "crypto/src/crmf/CertificateRequestMessage.cs"], "versions": [{"status": "affected", "version": "0", "lessThan": "2.7.0", "versionType": "semver"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "Allocation of resources without limits or throttling in the CMP/CRMF password-based MAC verifier (PKMacBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a CMP message or CRMF certificate request whose PBMParameter declares a very large iteration count, because PKMacBuilder enforced its iteration-count ceiling only when the caller had supplied an explicit maximum through the PKMacBuilder(IPKMacPrimitivesProvider, int) constructor. With any other constructor, ProtectedPkiMessage.Verify and CertificateRequestMessage.IsValidSigningKeyPop performed as many hash iterations as the sender requested, up to about 2^31, before the MAC could be checked.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "Allocation of resources without limits or throttling in the CMP/CRMF password-based MAC verifier (PKMacBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a CMP message or CRMF certificate request whose PBMParameter declares a very large iteration count, because PKMacBuilder enforced its iteration-count ceiling only when the caller had supplied an explicit maximum through the PKMacBuilder(IPKMacPrimitivesProvider, int) constructor. With any other constructor, ProtectedPkiMessage.Verify and CertificateRequestMessage.IsValidSigningKeyPop performed as many hash iterations as the sender requested, up to about 2^31, before the MAC could be checked."}]}], "references": [{"url": "https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63568", "tags": ["vendor-advisory"]}, {"url": "https://github.com/bcgit/bc-csharp/commit/10a9862fad04bb0c832a78b10e71d9818d6d1a63", "tags": ["patch"]}, {"url": "https://github.com/bcgit/bc-csharp/commit/65283bae66843d0d3c13c5e0272dbbe1c0d6aa04", "tags": ["patch"]}, {"url": "https://github.com/bcgit/bc-csharp/commit/d16f08a53dd0a78eb3310bbe80c947c7e1677290", "tags": ["patch"]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "HIGH", "baseScore": 8.7, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}}], "credits": [{"lang": "en", "value": "Discovered by Claude, Anthropic's AI assistant, and triaged by the Anthropic security team in collaboration with Anthropic Research.", "type": "finder"}], "source": {"discovery": "EXTERNAL"}, "x_generator": {"engine": "Claude Opus 5.5"}, "x_antReportIds": ["ANT-2026-BS6SFW9B", "ANT-2026-SGFCCBWB"]}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://www.nuget.org/packages/BouncyCastle.Cryptography", "defaultStatus": "unaffected", "packageName": "BouncyCastle.Cryptography", "product": "bc-csharp", "programFiles": ["crypto/src/crmf/PKMacBuilder.cs", "crypto/src/cmp/ProtectedPkiMessage.cs", "crypto/src/crmf/CertificateRequestMessage.cs"], "repo": "https://github.com/bcgit/bc-csharp", "vendor": "Legion of the Bouncy Castle Inc.", "versions": [{"lessThan": "2.7.0", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "91579145-5d7b-4cc5-b925-a0262ff19630"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Allocation of resources without limits or throttling in the CMP/CRMF password-based MAC verifier (PKMacBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a CMP message or CRMF certificate request whose PBMParameter declares a very large iteration count, because PKMacBuilder enforced its iteration-count ceiling only when the caller had supplied an explicit maximum through the PKMacBuilder(IPKMacPrimitivesProvider, int) constructor. With any other constructor, ProtectedPkiMessage.Verify and CertificateRequestMessage.IsValidSigningKeyPop performed as many hash iterations as the sender requested, up to about 2^31, before the MAC could be checked."}], "id": "CVE-2026-63568", "lastModified": "2026-10-02T07:16:37.267", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "91579145-5d7b-4cc5-b925-a0262ff19630", "type": "Secondary"}]}, "published": "2026-10-02T07:16:37.267", "references": [{"source": "91579145-5d7b-4cc5-b925-a0262ff19630", "url": "https://github.com/bcgit/bc-csharp/commit/10a9862fad04bb0c832a78b10e71d9818d6d1a63"}, {"source": "91579145-5d7b-4cc5-b925-a0262ff19630", "url": "https://github.com/bcgit/bc-csharp/commit/65283bae66843d0d3c13c5e0272dbbe1c0d6aa04"}, {"source": "91579145-5d7b-4cc5-b925-a0262ff19630", "url": "https://github.com/bcgit/bc-csharp/commit/d16f08a53dd0a78eb3310bbe80c947c7e1677290"}, {"source": "91579145-5d7b-4cc5-b925-a0262ff19630", "url": "https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63568"}], "sourceIdentifier": "91579145-5d7b-4cc5-b925-a0262ff19630", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-770"}], "source": "91579145-5d7b-4cc5-b925-a0262ff19630", "type": "Secondary"}]}

{}

{"created": "2026-10-02T09:00:18.758324+00:00", "updated": "2026-10-02T09:00:18.758330+00:00", "vendors": []}