{"id":"CVE-2026-59639","state":"PUBLISHED","title":"CMS verifySignatures returns true for SignedData with zero signers","description":"In Bouncy Castle for Java before 1.85, CMS verifySignatures returns true for SignedData with zero signers. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.12 (1.0.X series), 2.0.12 (2.0.X series) and 2.1.12 (2.1.X series).","publishedAt":"2026-08-03T00:56:24.394Z","updatedAt":"2026-08-03T13:24:16.359Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber","source":"bcorg"},"assigner":"bcorg","products":["Legion of the Bouncy Castle Inc. BC-JAVA","Legion of the Bouncy Castle Inc. BC-LTS-JAVA","Legion of the Bouncy Castle Inc. BC-FJA"],"affected":[{"vendor":"Legion of the Bouncy Castle Inc.","product":"BC-JAVA","packageName":"bcpkix","packageURL":"pkg:maven/org.bouncycastle/bcpkix-jdk18on","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.85","versionType":"maven"}],"platforms":["all"],"collectionURL":"https://www.bouncycastle.org/download/bouncy-castle-java/","repo":"https://github.com/bcgit/bc-java","modules":["pkix"],"programFiles":["CMSSignedData"]},{"vendor":"Legion of the Bouncy Castle Inc.","product":"BC-LTS-JAVA","packageName":"bcpkix-lts8on","packageURL":"pkg:maven/org.bouncycastle/bcpkix-lts8on","defaultStatus":"unaffected","versions":[{"version":"2.73.0","status":"affected","lessThan":"2.73.12","versionType":"maven"}],"platforms":["all"],"collectionURL":"https://www.bouncycastle.org/download/bouncy-castle-java-lts/","repo":"https://github.com/bcgit/bc-lts-java","modules":["pkix"],"programFiles":["CMSSignedData"]},{"vendor":"Legion of the Bouncy Castle Inc.","product":"BC-FJA","packageName":"bcpkix-fips","packageURL":"pkg:maven/org.bouncycastle/bcpkix-fips","defaultStatus":"unaffected","versions":[{"version":"1.0.0","status":"affected","lessThan":"1.0.12","versionType":"maven"},{"version":"2.0.0","status":"affected","lessThan":"2.0.12","versionType":"maven"},{"version":"2.1.0","status":"affected","lessThan":"2.1.12","versionType":"maven"}],"platforms":["all"],"collectionURL":"https://www.bouncycastle.org/download/bouncy-castle-java-fips/"}],"references":["https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059639","https://github.com/bcgit/bc-java/commit/99ddc6dcc6782e6a76b0dd587c77e62eb7096ad0"],"weaknesses":["CWE-347"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/59xxx/CVE-2026-59639.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59639","state":"PUBLISHED","datePublished":"2026-08-03T00:56:24.394Z","dateUpdated":"2026-08-03T13:24:16.359Z","assignerShortName":"bcorg","assignerOrgId":"91579145-5d7b-4cc5-b925-a0262ff19630","dateReserved":"2026-07-06T06:58:29.263Z"},"containers":{"cna":{"title":"CMS verifySignatures returns true for SignedData with zero signers","descriptions":[{"lang":"en","value":"In Bouncy Castle for Java before 1.85, CMS verifySignatures returns true for SignedData with zero signers. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.12 (1.0.X series), 2.0.12 (2.0.X series) and 2.1.12 (2.1.X series)."}],"affected":[{"vendor":"Legion of the Bouncy Castle Inc.","product":"BC-JAVA","packageName":"bcpkix","packageURL":"pkg:maven/org.bouncycastle/bcpkix-jdk18on","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.85","versionType":"maven"}],"platforms":["all"],"collectionURL":"https://www.bouncycastle.org/download/bouncy-castle-java/","repo":"https://github.com/bcgit/bc-java","modules":["pkix"],"programFiles":["CMSSignedData"]},{"vendor":"Legion of the Bouncy Castle Inc.","product":"BC-LTS-JAVA","packageName":"bcpkix-lts8on","packageURL":"pkg:maven/org.bouncycastle/bcpkix-lts8on","defaultStatus":"unaffected","versions":[{"version":"2.73.0","status":"affected","lessThan":"2.73.12","versionType":"maven"}],"platforms":["all"],"collectionURL":"https://www.bouncycastle.org/download/bouncy-castle-java-lts/","repo":"https://github.com/bcgit/bc-lts-java","modules":["pkix"],"programFiles":["CMSSignedData"]},{"vendor":"Legion of the Bouncy Castle Inc.","product":"BC-FJA","packageName":"bcpkix-fips","packageURL":"pkg:maven/org.bouncycastle/bcpkix-fips","defaultStatus":"unaffected","versions":[{"version":"1.0.0","status":"affected","lessThan":"1.0.12","versionType":"maven"},{"version":"2.0.0","status":"affected","lessThan":"2.0.12","versionType":"maven"},{"version":"2.1.0","status":"affected","lessThan":"2.1.12","versionType":"maven"}],"platforms":["all"],"collectionURL":"https://www.bouncycastle.org/download/bouncy-castle-java-fips/"}],"references":[{"url":"https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059639","tags":["vendor-advisory"]},{"url":"https://github.com/bcgit/bc-java/commit/99ddc6dcc6782e6a76b0dd587c77e62eb7096ad0","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":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"AMBER","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:H/VA:N/SC:N/SI:N/SA:N/U:Amber"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","lang":"en","description":"CWE-347 Improper Verification of Cryptographic Signature","type":"CWE"}]}],"providerMetadata":{"shortName":"bcorg","orgId":"91579145-5d7b-4cc5-b925-a0262ff19630","dateUpdated":"2026-08-03T05:05:39.619Z"},"credits":[{"lang":"en","value":"Alex Gaynor in collaboration with Claude and Anthropic Research","type":"reporter"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"bc release-notes template"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-03T13:24:06.309527Z","id":"CVE-2026-59639","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-03T13:24:16.359Z"}}]}}}