{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-63566 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-63566 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-63566 is a high-severity denial of service vulnerability in Legion of the Bouncy Castle Inc. bc-csharp, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-63566 and fix it if it is affected.\n\nWhat it is: CVE-2026-63566 is a high-severity denial of service vulnerability in Legion of the Bouncy Castle Inc. bc-csharp, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-63566 in the wild and no public exploit code.\n\nAffected product: Legion of the Bouncy Castle Inc. bc-csharp. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-63566/ (Markdown: https://insights.sbomify.com/CVE-2026-63566/index.md)","id":"CVE-2026-63566","markdown":"https://insights.sbomify.com/CVE-2026-63566/index.md","name":"CVE-2026-63566","record":{"aliases":["GHSA-496x-2f25-59fj"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"C# cryptography library","requires_auth":"none","summary":"Remote attackers can cause denial of service via memory exhaustion in DTLS handshake reassembly by sending crafted fragments with unchecked length values.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"bcorg","cpe":[{"product":"bc-csharp","vendor":"bouncycastle"}],"cvss":{"score":8.7,"severity":"high","source":"cna","vector":"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","version":"4.0"},"cwes":[{"id":"CWE-789","name":"Memory Allocation with Excessive Size Value"}],"description":"Memory allocation with excessive size value in the DTLS handshake reassembly (DtlsReliableHandshake, DtlsReassembler) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated DTLS peer to cause a denial of service through memory exhaustion via crafted handshake message fragments, because the reassembly buffer for each incoming handshake message was allocated at the 24-bit length declared in the fragment header, without the check against the peer's maximum handshake message size that TLS already applied. A fragment carrying no payload can force an allocation of almost 16 MB, for each of up to 16 pending messages per handshake, before the handshake is authenticated. DTLS servers and DTLS clients are both affected; TLS is not.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":false,"headline":"DTLS handshake reassembler allocates buffer from unchecked 24-bit length","id":"CVE-2026-63566","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"IesEngine block-cipher mode checks padding before MAC (CBC padding oracle)","id":"CVE-2026-63567"},"packages":[],"prev":{"headline":"Misconfiguration in Sharp MFPs","id":"CVE-2026-63563"},"products":["bc-csharp"],"published":"2026-10-02","related":[{"cvss_score":9.1,"headline":"MTI/A0 DHAgreement does not validate the peer's ephemeral value","id":"CVE-2026-63569","kev_date_added":null,"published":"2026-10-02"},{"cvss_score":8.7,"headline":"Unbounded ASN.1 nesting depth causes process-terminating stack overflow","id":"CVE-2026-103600","kev_date_added":null,"published":"2026-10-02"},{"cvss_score":8.7,"headline":"Unbounded HSS public key level count allows huge array allocation during signature verification","id":"CVE-2026-103603","kev_date_added":null,"published":"2026-10-02"},{"cvss_score":8.7,"headline":"Quadratic-time escaping when converting X.509 distinguished names to strings","id":"CVE-2026-103604","kev_date_added":null,"published":"2026-10-02"},{"cvss_score":8.7,"headline":"KCcmBlockCipher (DSTU 7624 CCM) tag not bound to nonce when no associated data is used","id":"CVE-2026-16000","kev_date_added":null,"published":"2026-10-02"},{"cvss_score":8.7,"headline":"Unbounded CMP/CRMF password-based MAC iteration count allows CPU exhaustion","id":"CVE-2026-63568","kev_date_added":null,"published":"2026-10-02"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-02","vendors":["Legion of the Bouncy Castle Inc."]},"summary":"Remote attackers can cause denial of service via memory exhaustion in DTLS handshake reassembly by sending crafted fragments with unchecked length values.","url":"https://insights.sbomify.com/CVE-2026-63566/"}