Global cybersecurity authorities have published a joint advisory on the 15 Common Vulnerabilities and Exposures (CVEs) most routinely exploited by malicious cyber actors in 2021. The advisory is co-authored by the U.S. Cybersecurity and Infrastructure Security Agency (CISA), U.S. National Security Agency (NSA), U.S. Federal Bureau of Investigation (FBI), Australian Cyber Security Centre (ACSC), Canadian Centre for Cyber Security (CCCS), New Zealand National Cyber Security Centre (NZ NCSC), and United Kingdom’s National Cyber Security Centre (NCSC-UK).