CVE-2019-11873

CVE-2019-11873 describes a critical buffer overflow vulnerability in wolfSSL version 4.0.0, specifically within the DoPreSharedKeys function in tls13.c. An unauthenticated attacker can trigger this by sending a specially crafted TLSv1.3 client hello packet with oversized length fields and identity data, leading to a 65KB write to undefined memory on the server. This vulnerability carries a CVSS score of 9.8 (Critical) due to its network-based attack vector, low attack complexity, and potential for remote code execution, resulting in high impacts to confidentiality, integrity, and availability. Despite its severity, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.