{"id":"CVE-2026-63570","summary":"Pkcs12Store.GetCertificateChain loops forever on cyclic issuer links","details":"Loop with unreachable exit condition in Pkcs12Store.GetCertificateChain in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply a crafted PKCS#12 file to an application that loads it and requests a key entry's certificate chain to cause a denial of service, in which the call never returns and consumes CPU and memory until an OutOfMemoryException, via certificates whose issuer links form a cycle, for example two certificates whose AuthorityKeyIdentifier extensions each identify the other's public key. This happens because the chain-building loop stops only when no issuer is found or a certificate links to itself, and keeps no record of certificates already visited. The key-identifier links are followed without checking signatures.","modified":"2026-10-04T02:46:44.330701302Z","published":"2026-10-02T07:01:18.029Z","database_specific":{"cwe_ids":["CWE-835"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63570.json","cna_assigner":"bcorg"},"references":[{"type":"WEB","url":"https://www.nuget.org/packages/BouncyCastle.Cryptography"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63570.json"},{"type":"ADVISORY","url":"https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63570"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63570"},{"type":"FIX","url":"https://github.com/bcgit/bc-csharp/commit/1b8fad04df4953230c9951c57678ee45c8aead85"},{"type":"PACKAGE","url":"https://github.com/bcgit/bc-csharp"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/bcgit/bc-csharp","events":[{"introduced":"0"},{"fixed":"4007498b13582d90ee1eda5d9920c324428b98b3"},{"fixed":"1b8fad04df4953230c9951c57678ee45c8aead85"}],"database_specific":{"source":["DESCRIPTION","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"2.7.0"}]}}],"versions":["release-1.9.0","release-1.8.10","release-1.8.8","release-1.8.7","release-1.8.6","release-1.8.5","release-1.8.4","release-1.8.3","release-1.8.2","release-1.8.1","release-1.8.0","release-1.8.0-RC.3","release-1.8.0-RC.2","release-1.8.0-RC.1","release-1.8.0-beta.4","release-1.8.0-beta.3","release-1.8.0-beta.2","release-1.8.0-beta.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63570.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}