The US Cybersecurity and Infrastructure Security Agency (CISA) on Tuesday announced that it has added 15 vulnerabilities to its Known Exploited Vulnerabilities Catalog.

More than 500 security flaws have been added to the “Must-Patch” list since November 2021, when CISA first announced it, along with Binding Operational Directive 22-01, which requires federal agencies to take prompt action to address the identified issues.

The newly added flaws – one affecting SonicWall SonicOS and 14 impacting Microsoft Windows – are older issues, some of them having been patched for more than half a decade.

The SonicOS security hole (CVE-2020-5135) can be exploited for DoS attacks and arbitrary code execution. The Windows flaws – patched between 2016 and 2019 – can all lead to privilege escalation.

[ READ: CISA’s ‘Must Patch’ List Puts Spotlight on Vulnerability Management Processes ]

CISA is asking federal agencies to address the newly flagged security defects by April 5, which is surprising, given that previously organizations were given half a year to resolve older flaws.

Although CISA created the Known Exploited Vulnerabilities Catalog to help federal agencies with their vulnerability management operations, all organizations are advised to review the list and address the identified flaws as soon as possible.

In January, the agency told SecurityWeek that it has evidence that all of the vulnerabilities included in the Must-Patch list have been exploited in attacks, even if no public reports mention exploitation for some of them.

The catalog, CISA said, was created to help organizations in both public and private sectors reduce exposure to cyberattacks by improving vulnerability management capabilities.

Related: CISA Urges Organizations to Patch Recent Firefox Zero-Days

Related: CISA Says Recent Cisco Router Vulnerabilities Exploited in Attacks

Related: CISA Urges Organizations to Patch Actively Exploited Zimbra XSS Vulnerability

Ionut Arghire is an international correspondent for SecurityWeek.

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