Threats / Nagios / CVE-2021-25296
CVE-2021-25296
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Nagios XI vulnerability
Nagios XI is vulnerable to OS command injection, allowing attackers to execute arbitrary commands on the affected server.
Verdict
Today item — known-exploited.
A command injection flaw in Nagios XI enables unauthenticated or low-privileged attackers to execute arbitrary operating system commands with the privileges of the Nagios process, potentially compromising the entire monitoring infrastructure.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
3 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-01-18).
Probability (EPSS)
EPSS 0.72378 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Nagios, Nagios XI. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-78 OS Command Injection, CWE-138 CWE-138 — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious input containing shell metacharacters to inject OS commands into a vulnerable Nagios XI parameter.
Business
The organization loses control of its monitoring infrastructure, which is often a critical operational dependency.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute commands with the privileges of the Nagios XI process to establish persistence or pivot to other systems.
Business
Attackers gain a foothold in the network, enabling lateral movement and compromise of dependent systems and data.
3
Lateral reach — past segmentation narrative 3
Attacker
I exfiltrate sensitive configuration data, credentials, or monitoring data stored on the Nagios XI server.
Business
Confidential operational and security information is exposed, increasing risk of further targeted attacks.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05