Abstract Zero-day vulnerabilities remain one of the major security threats that are faced by organizations. Once a vendor learns about a zero-day vulnerability, releasing a timely patch becomes a priority given the risk of zero-day exploits. However, we still lack information on the factors that affect patch release time of such vulnerabilities. The main objective of this study is to examine the impact of other as-yet unexplored factors on the patch release time of zero-day vulnerabilities. Using zero-day vulnerability dataset captured between 2010 and 2020, we employ survival analysis technique. Our model explores the impact of vulnerability attack vector, attack complexity, privileges required, user interaction, scope, confidentiality, integrity, and availability impact on patch release timing. Findings show that a zero-day vulnerability is more likely to be patched on time if the vulnerability results in a scope change and affects more vendors, products, and versions. However, a zero-day vulnerability is less likely to be patched on time if it requires privileges and impacts confidentiality. Our sub-analyses also reveal how patch release times vary across different products and vulnerability types.