{"cve":"CVE-2021-4300","nvd":{"published":"2023-01-04T22:15:08.903","modified":"2026-06-17T04:19:27.370","status":"Modified","description":"A vulnerability has been found in ghostlander Halcyon and classified as critical. Affected by this vulnerability is the function CBlock::AddToBlockIndex of the file src/main.cpp of the component Block Verification. The manipulation leads to improper access controls. The attack can be launched remotely. Upgrading to version 1.1.1.0-hal is able to address this issue. The identifier of the patch is 0675b25ae9cc10b5fdc8ea3a32c642979762d45e. It is recommended to upgrade the affected component. The identifier VDB-217417 was assigned to this vulnerability.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-284"],"references":["https://github.com/ghostlander/Halcyon/commit/0675b25ae9cc10b5fdc8ea3a32c642979762d45e","https://github.com/ghostlander/Halcyon/releases/tag/v1.1.1.0-hal","https://vuldb.com/?ctiid.217417","https://vuldb.com/?id.217417","https://github.com/ghostlander/Halcyon/commit/0675b25ae9cc10b5fdc8ea3a32c642979762d45e"],"products":["halcyon_project:halcyon"],"source":"nvd","synced_at":"2026-10-19T21:37:31.370122805+00:00"},"epss":{"cve":"CVE-2021-4300","score":0.00689,"percentile":0.5276,"date":"2026-10-31"},"kev":null,"osv":[],"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."]}