{"schema":"threatline.record/2","record":{"id":"CVE-2026-103600","aliases":[],"summary":"Unbounded ASN.1 nesting depth causes process-terminating stack overflow","details":"Uncontrolled recursion in the ASN.1 parser (Asn1InputStream, Asn1StreamParser) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service via a crafted ASN.1 encoding of deeply nested constructed elements (for example SEQUENCE inside SEQUENCE, in definite-length DER or indefinite-length BER form), because each nesting level is parsed by a further recursive call with no bound on depth. About 2,000 levels (8 KB of DER) are enough to exhaust a 1.5 MB thread stack, the .NET main-thread default on Windows, and raise a StackOverflowException, which .NET cannot catch and which terminates the whole process; on threads with larger stacks, parse time instead grows quadratically with depth (about 9 seconds of CPU for a 64 KB input). Any path that parses untrusted ASN.1 is exposed, including X.509 certificates and CRLs, CMS/PKCS#7, PKCS#8/PKCS#12, OCSP and TLS Certificate messages.","categories":["Unclassified"],"product":"bc-csharp","vendor":"Legion of the Bouncy Castle Inc.","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-103600","source_modified_at":"2026-10-02T17:54:00.089Z","fetched_at":"2026-10-23T18:52:38.922436Z","product":"bc-csharp","vendor":"Legion of the Bouncy Castle Inc.","versions":[{"status":"affected","version":"0","lessThan":"2.7.0","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-103600","source_modified_at":"2026-10-02T17:54:00.089Z","fetched_at":"2026-10-23T18:52:38.922436Z","package":{"name":"bc-csharp","ecosystem":null},"version":"2.7.0","basis":"first unaffected version stated in the CVE record"}],"cvss":8.7,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00315,"percentile":0.23239,"score_date":"2026-10-23"},"published_at":"2026-10-02T07:08:51.653Z","modified_at":"2026-10-02T17:54:00.089Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-103600","fetched_at":"2026-10-23T18:52:38.922436Z","source_modified_at":"2026-10-02T17:54:00.089Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-103600","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/bcgit/bc-csharp/wiki/CVE-2026-103600","tags":["vendor-advisory"]},{"source":"CVE List","url":"https://github.com/bcgit/bc-csharp/commit/89c81b0da7fe11cd70013285560bbc472cb73901","tags":["patch"]},{"source":"CVE List","url":"https://github.com/bcgit/bc-csharp/commit/b99f4e3dcea05b57becc79dfa6ad91a54c778d65","tags":["patch"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"partial","assessed_at":"2026-10-02T17:53:50.650326Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-02T17:54:00.089Z","content_hash":"133fc4fb4d01d90acc77931464ea4ccc5e5053f8fed2d87a6ce89a687d795589"}}