{"cve":"CVE-2021-45699","nvd":{"published":"2021-12-27T00:15:09.623","modified":"2026-06-17T04:13:58.337","status":"Modified","description":"An issue was discovered in the ckb crate before 0.40.0 for Rust. Remote attackers may be able to conduct a 51% attack against the Nervos CKB blockchain by triggering an inability to allocate memory for the misbehavior HashMap.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-770"],"references":["https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/ckb/RUSTSEC-2021-0108.md","https://rustsec.org/advisories/RUSTSEC-2021-0108.html","https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/ckb/RUSTSEC-2021-0108.md","https://rustsec.org/advisories/RUSTSEC-2021-0108.html"],"products":["nervos:ckb"],"source":"nvd","synced_at":"2026-10-19T21:26:33.761856376+00:00"},"epss":{"cve":"CVE-2021-45699","score":0.01515,"percentile":0.74513,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-2969-8hh9-57jc","url":"https://osv.dev/vulnerability/GHSA-2969-8hh9-57jc","summary":"Allocation of Resources Without Limits or Throttling in ckb","modified":"2023-11-08T04:07:22.625998Z","packages":[{"ecosystem":"crates.io","name":"ckb","purl":"pkg:cargo/ckb","ranges":["<0.40.0"],"fixed":["0.40.0"]}]},{"id":"GHSA-48vq-8jqv-gm6f","url":"https://osv.dev/vulnerability/GHSA-48vq-8jqv-gm6f","summary":"Remote memory exhaustion in ckb","modified":"2023-11-08T04:07:22.625998Z","packages":[{"ecosystem":"crates.io","name":"ckb","purl":"pkg:cargo/ckb","ranges":["<0.40.0"],"fixed":["0.40.0"]}]},{"id":"RUSTSEC-2021-0108","url":"https://osv.dev/vulnerability/RUSTSEC-2021-0108","summary":"Remote memory exhaustion in ckb","modified":"2026-10-12T18:00:05.111824805Z","packages":[{"ecosystem":"crates.io","name":"ckb","purl":"pkg:cargo/ckb","ranges":[">=0.0.0-0 <0.40.0"],"fixed":["0.40.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}