How severe is CVE-2020-28903?

CVE-2020-28903 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-28903 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-28903?

CVE-2020-28903 affects Nagios Fusion. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-28903?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-28903 published?

CVE-2020-28903 was published on 2021-05-24 and last updated on 2026-06-17.

CVE-2020-28903

CVE-2020-28903 is a medium-severity vulnerability in Nagios Fusion with a CVSS 3.x base score of 6.1. Its EPSS exploit-prediction score of 10% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 10% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Nagios Fusion
Published: 2021-05-24
Last modified: 2026-06-17

Description

Improper input validation in Nagios Fusion 4.1.8 and earlier allows a remote attacker with control over a fused server to inject arbitrary HTML, aka XSS.

Frequently asked questions

What is CVE-2020-28903?: Improper input validation in Nagios Fusion 4.1.8 and earlier allows a remote attacker with control over a fused server to inject arbitrary HTML, aka XSS.
How severe is CVE-2020-28903?: CVE-2020-28903 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-28903 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-28903?: CVE-2020-28903 affects Nagios Fusion. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-28903?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-28903 published?: CVE-2020-28903 was published on 2021-05-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nagios:fusion:*:*:*:*:*:*:*:*

More vulnerabilities in Nagios Fusion

CVE-2020-28908 — Critical (CVSS 9.8): Command Injection in Nagios Fusion 4.1.8 and earlier allows for Privilege Escalation to nagios.
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CVE-2020-28902 — Critical (CVSS 9.8): Command Injection in Nagios Fusion 4.1.8 and earlier allows Privilege Escalation from apache to root in cmd_subsys.php.
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CVE-2020-28900 — Critical (CVSS 9.8): Insufficient Verification of Data Authenticity in Nagios Fusion 4.1.8 and earlier and Nagios XI 5.7.5 and earlier…

All CVEs affecting Nagios Fusion →

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