Vinchin Backup & Recovery through 9.0.0.86562 contains a heap buffer overflow vulnerability that allows unauthenticated remote attackers to cause process crash or memory corruption by sending a malformed TCP packet with an unchecked body_len field to the agentlink_server service. Attackers can craft a malicious packet that passes an attacker-controlled length directly to recv(), triggering a heap overflow of up to approximately 4 GiB and resulting in process crash or potential memory corruption.