How severe is CVE-2021-26023?

CVE-2021-26023 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-2021-26023 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 25% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26023?

CVE-2021-26023 affects Nagios Favorites. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26023?

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

When was CVE-2021-26023 published?

CVE-2021-26023 was published on 2021-02-03 and last updated on 2026-06-17.

CVE-2021-26023

CVE-2021-26023 is a medium-severity vulnerability in Nagios Favorites with a CVSS 3.x base score of 6.1. Its EPSS exploit-prediction score of 25% places it in the 98th 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: 25% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Nagios Favorites
Published: 2021-02-03
Last modified: 2026-06-17

Description

The Favorites component before 1.0.2 for Nagios XI 5.8.0 is vulnerable to XSS.

Frequently asked questions

What is CVE-2021-26023?: The Favorites component before 1.0.2 for Nagios XI 5.8.0 is vulnerable to XSS.
How severe is CVE-2021-26023?: CVE-2021-26023 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-2021-26023 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 25% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26023?: CVE-2021-26023 affects Nagios Favorites. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26023?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26023 published?: CVE-2021-26023 was published on 2021-02-03 and last updated on 2026-06-17.

References

https://www.nagios.com/products/security/

Affected products (1)

cpe:2.3:a:nagios:favorites:*:*:*:*:*:*:*:*

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