CVE-2019-1551

CVE-2019-1551 describes an overflow bug in the x64_64 Montgomery squaring procedure within OpenSSL versions 1.1.1 through 1.1.1d and 1.0.2 through 1.0.2t, affecting exponentiation with 512-bit moduli. While RSA and DSA attacks are unlikely, attacks against DH512 are considered feasible if the private key is reused, and applications using BN_mod_exp with BN_FLG_CONSTTIME may also be vulnerable. Rated Medium (CVSS 5.3), this vulnerability has a network attack vector with low complexity, potentially leading to information disclosure. The primary impact is on confidentiality, with no integrity or availability impact. There is no evidence of active exploitation, no public exploit code (Metasploit, Nuclei, ExploitDB), and minimal community discussion or media coverage, suggesting low current threat activity.