CVE-2021-4300

CVE-2021-4300 is a critical improper access control vulnerability in the CBlock::AddToBlockIndex function within the Block Verification component of ghostlander Halcyon. This flaw, affecting halcyon_project halcyon, allows for remote attacks. With a CVSS score of 9.8 (Critical), it presents a high risk due to its network-based attack vector, low attack complexity, and complete compromise of confidentiality, integrity, and availability. While there is no evidence of active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered significant community discussion, indicating awareness and potential interest.