How severe is CVE-2021-25933?

CVE-2021-25933 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-25933 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-25933?

CVE-2021-25933 primarily affects Opennms Horizon. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-25933?

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

When was CVE-2021-25933 published?

CVE-2021-25933 was published on 2021-05-20 and last updated on 2026-06-17.

CVE-2021-25933

CVE-2021-25933 is a medium-severity vulnerability in Opennms Horizon with a CVSS 3.x base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
CVSS v2: 3.5
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Opennms Horizon
Published: 2021-05-20
Last modified: 2026-06-17

Description

In OpenNMS Horizon, versions opennms-1-0-stable through opennms-27.1.0-1; OpenNMS Meridian, versions meridian-foundation-2015.1.0-1 through meridian-foundation-2019.1.18-1; meridian-foundation-2020.1.0-1 through meridian-foundation-2020.1.6-1 are vulnerable to Stored Cross-Site Scripting, since the function `validateFormInput()` performs improper validation checks on the input sent to the `groupName` and `groupComment` parameters. Due to this flaw, an authenticated attacker could inject arbitrary script and trick other admin users into downloading malicious files which can cause severe damage to the organization using opennms.

Frequently asked questions

What is CVE-2021-25933?: In OpenNMS Horizon, versions opennms-1-0-stable through opennms-27.1.0-1; OpenNMS Meridian, versions meridian-foundation-2015.1.0-1 through meridian-foundation-2019.1.18-1; meridian-foundation-2020.1.0-1 through meridian-foundation-2020.1.6-1 are vulnerable to Stored Cross-Site Scripting, since the function `validateFormInput()` performs improper validation checks on the input sent to the `groupName` and `groupComment` parameters. Due to this flaw, an authenticated attacker could inject arbitrary script and trick other admin users into downloading malicious files which can cause severe damage to the organization using opennms.
How severe is CVE-2021-25933?: CVE-2021-25933 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-25933 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-25933?: CVE-2021-25933 primarily affects Opennms Horizon. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-25933?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-25933 published?: CVE-2021-25933 was published on 2021-05-20 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:opennms:horizon:*:*:*:*:*:*:*:*
cpe:2.3:a:opennms:meridian:*:*:*:*:*:*:*:*

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