Press Release

CISA, FBI, NSA, and International Partners Warn Organizations of Top Routinely Exploited Cybersecurity Vulnerabilities   


WASHINGTON –  The Cybersecurity and Infrastructure Security Agency (CISA), National Security Agency (NSA), 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 the United Kingdom’s National Cyber Security Centre (NCSC-UK) issued a joint Cybersecurity Advisory today on the common vulnerabilities and exposures (CVEs) frequently exploited by malicious cyber actors, including the 15 most commonly exploited of 2021.   

Malicious cyber actors continue to aggressively target disclosed critical software vulnerabilities against broad target sets in both the public and private sectors. While the top 15 vulnerabilities have previously been made public, this Advisory is meant to help organizations prioritize their mitigation strategies.

The cybersecurity authorities recommend the following prioritized mitigation measures:    

  • Vulnerability and configuration management, including updating software, operating systems, applications, and firmware, with a prioritization on patching known exploited vulnerabilities; implementing a centralized patch management system; and replacing end-of-life software.   
  • Identity and access management, including enforcing multi-factor authentication (MFA) for all users; if MFA is unavailable, require employees engaging in remote work to use strong passwords; and regularly reviewing, validating, or removing privileged accounts.    
  • Protective controls and architecture, including properly configuring and secure internet-facing network devices, disabling unused or unnecessary network ports and protocols, encrypting network traffic, and disabling unused network services and devices.    

“We know that malicious cyber actors go back to what works, which means they target these same critical software vulnerabilities and will continue to do so until companies and organizations address them,” said CISA Director Jen Easterly. “CISA and our partners are releasing this advisory to highlight the risk that the most commonly exploited vulnerabilities pose to both public and private sector networks. We urge all organizations to assess their vulnerability management practices and take action to mitigate risk to the known exploited vulnerabilities.”   

"This report should be a reminder to organizations that bad actors don't need to develop sophisticated tools when they can just exploit publicly known vulnerabilities," said NSA Cybersecurity Director Rob Joyce. "Get a handle on mitigations or patches as these CVEs are actively exploited.” 

"The FBI, together with our federal and international partners, is providing this information to better arm our private sector partners and the public to defend their systems from adversarial cyber threats," said FBI's Cyber Division Assistant Director Bryan Vorndran. "Though the FBI will continue to pursue and disrupt this type of malicious cyber activity, we need your help. We strongly encourage private sector organizations and the public to implement these steps to mitigate threats from known vulnerabilities, and if you believe you are a victim of a cyber incident, contact your local FBI field office."  

“Malicious cyber actors continue to exploit known and dated software vulnerabilities to attack private and public networks globally,” said Abigail Bradshaw, Head of the Australian Cyber Security Centre. “The ACSC is committed to providing cyber security advice and sharing threat information with our partners, to ensure a safer online environment for everyone. Organisations can implement the effective mitigations highlighted in this advisory to protect themselves.”  

“Cyber security best practices, including patch management, are essential tools for organizations to better protect themselves against malicious threat actors,” said Sami Khoury, Head of the Canadian Centre for Cyber Security. “We encourage all organizations to take action and follow the appropriate mitigations in this report against known and routinely exploited vulnerabilities, and make themselves more secure.”  

“We are seeing an increase in the speed and scale of malicious actors taking advantage of newly disclosed vulnerabilities,” said Lisa Fong, Director of the New Zealand Government Communications Security Bureau’s National Cyber Security Centre (NCSC). “The NCSC works with international partners to provide timely access to critical cyber threat information. This joint advisory underscores the importance of addressing vulnerabilities as they are disclosed and better equips New Zealand organisations to secure their information and systems.”  

“The NCSC and our allies are committed to raising awareness of global cyber vulnerabilities and presenting actionable solutions to mitigate them,” said Lindy Cameron, CEO of NCSC. “This advisory places the power in the hands of network defenders to fix the most common cyber weaknesses within the public and private sector ecosystem. Working with our international partners, we will continue to raise awareness of the threats posed by those which seek to harm us.” 

All organizations are encouraged to review and implement the recommended mitigations in this detailed joint CSA.    

Organizations should share information about incidents and unusual cyber activity with their respective cybersecurity authorities. When cyber incidents are reported quickly, it can contribute to stopping further attacks. In the U.S., organizations can also report anomalous cyber activity and/or cyber incidents 24/7 to or by calling 1-844-Say-CISA (1-844-729-2472), or an FBI field office.    

About CISA:   

As the nation’s cyber defense agency, the Cybersecurity and Infrastructure Security Agency (CISA) leads the national effort to understand, manage, and reduce risk to the digital and physical infrastructure Americans rely on every hour of every day. Visit for more information, or visit for information on how to protect your networks.  
Visit CISA on Twitter, Facebook, LinkedIn, Instagram