{"api_version":"1","generated_at":"2026-04-15T21:30:51+00:00","cve":"CVE-2026-5588","urls":{"html":"https://cve.report/CVE-2026-5588","api":"https://cve.report/api/cve/CVE-2026-5588.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-5588","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-5588"},"summary":{"title":"PKIX draft CompositeVerifier accepts empty signature sequence as valid.","description":": Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).\n\n\nPKIX draft CompositeVerifier accepts empty signature sequence as valid.\n\n\nThis issue affects BC-JAVA: from 1.49 before 1.84.","state":"PUBLISHED","assigner":"bcorg","published_at":"2026-04-15 10:16:49","updated_at":"2026-04-15 17:17:06"},"problem_types":["CWE-327","CWE-327 CWE-327: Use of a Broken or Risky Cryptographic Algorithm"],"metrics":[{"version":"4.0","source":"91579145-5d7b-4cc5-b925-a0262ff19630","type":"Secondary","score":"6.3","severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/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:Green","data":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/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:Green","baseScore":6.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"GREEN"}},{"version":"4.0","source":"CNA","type":"CVSS","score":"6.3","severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/U:Green","data":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"GREEN","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/U:Green","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"}}],"references":[{"url":"https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905588","name":"https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905588","refsource":"91579145-5d7b-4cc5-b925-a0262ff19630","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-5588","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-5588","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Legion of the Bouncy Castle Inc.","product":"BC-JAVA","version":"affected 1.67 1.84 maven","platforms":["all"]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Nicholas Carlini using Claude, Anthropic","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-5588","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","timestamp":"2026-04-15T13:11:19.255996Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-04-15T13:11:24.398Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"collectionURL":"https://www.bouncycastle.org/download/bouncy-castle-java/","defaultStatus":"unaffected","modules":["pkix"],"packageName":"bcpkix","platforms":["all"],"product":"BC-JAVA","repo":"https://github.com/bcgit/bc-java","vendor":"Legion of the Bouncy Castle Inc.","versions":[{"lessThan":"1.84","status":"affected","version":"1.67","versionType":"maven"}]}],"credits":[{"lang":"en","type":"finder","value":"Nicholas Carlini using Claude, Anthropic"}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":": Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).<div><br></div><div>PKIX draft CompositeVerifier accepts empty signature sequence as valid.</div><div><br><p>This issue affects BC-JAVA: from 1.49 before 1.84.</p></div>"}],"value":": Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).\n\n\nPKIX draft CompositeVerifier accepts empty signature sequence as valid.\n\n\nThis issue affects BC-JAVA: from 1.49 before 1.84."}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"GREEN","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/U:Green","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-327","description":"CWE-327: Use of a Broken or Risky Cryptographic Algorithm","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-04-15T15:59:05.007Z","orgId":"91579145-5d7b-4cc5-b925-a0262ff19630","shortName":"bcorg"},"references":[{"url":"https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905588"}],"source":{"discovery":"UNKNOWN"},"title":"PKIX draft CompositeVerifier accepts empty signature sequence as valid.","x_generator":{"engine":"Vulnogram 1.0.1"}}},"cveMetadata":{"assignerOrgId":"91579145-5d7b-4cc5-b925-a0262ff19630","assignerShortName":"bcorg","cveId":"CVE-2026-5588","datePublished":"2026-04-15T09:06:15.617Z","dateReserved":"2026-04-04T23:50:59.336Z","dateUpdated":"2026-04-15T15:59:05.007Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-15 10:16:49","lastModifiedDate":"2026-04-15 17:17:06","problem_types":["CWE-327","CWE-327 CWE-327: Use of a Broken or Risky Cryptographic Algorithm"],"metrics":{"cvssMetricV40":[{"source":"91579145-5d7b-4cc5-b925-a0262ff19630","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/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:Green","baseScore":6.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"GREEN"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"5588","Ordinal":"1","Title":"PKIX draft CompositeVerifier accepts empty signature sequence as","CVE":"CVE-2026-5588","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"5588","Ordinal":"1","NoteData":": Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).\n\n\nPKIX draft CompositeVerifier accepts empty signature sequence as valid.\n\n\nThis issue affects BC-JAVA: from 1.49 before 1.84.","Type":"Description","Title":"PKIX draft CompositeVerifier accepts empty signature sequence as"}]}}}