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CVE-2021-25297 in Nagios Nagios XI: known exploited

Generated from its entry in CISA's catalogue of known exploited vulnerabilities as of 3 November 2026.

Attackers are exploiting CVE-2021-25297 in Nagios Nagios XI. CISA has listed it as known exploited since 18 January 2022.

ProductNagios Nagios XI
Known exploited since18 January 2022
Ransomware useNot recorded
EU vulnerability databaseEUVD-2021-12197
SourcesNVD · CISA KEV

What it means

Attackers have used this vulnerability in real attacks. An unpatched Nagios Nagios XI that can be reached from the internet is exposed to them.

What to do

  1. Apply the vendor's fix to every system running Nagios Nagios XI, starting with those reachable from the internet. Take a system off the internet until it can be fixed.
  2. Check the system for signs that it was reached before the fix.

How Vardion finds it

Wherever a scan or your imported scanner results find CVE-2021-25297, Vardion names the systems affected and puts the fix at the top of the list.

Know before an attacker does

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