How severe is CVE-2021-41836?

CVE-2021-41836 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-2021-41836 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41836?

CVE-2021-41836 affects Conva Fathom Analytics. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-41836?

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

When was CVE-2021-41836 published?

CVE-2021-41836 was published on 2021-12-14 and last updated on 2026-06-17.

CVE-2021-41836

CVE-2021-41836 is a medium-severity vulnerability in Conva Fathom Analytics 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% (43rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Conva Fathom Analytics
Published: 2021-12-14
Last modified: 2026-06-17

Description

The Fathom Analytics WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and escaping via the $site_id parameter found in the ~/fathom-analytics.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 3.0.4. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.

Frequently asked questions

What is CVE-2021-41836?: The Fathom Analytics WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and escaping via the $site_id parameter found in the ~/fathom-analytics.php file which allowed attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 3.0.4. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.
How severe is CVE-2021-41836?: CVE-2021-41836 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-2021-41836 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41836?: CVE-2021-41836 affects Conva Fathom Analytics. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41836?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-41836 published?: CVE-2021-41836 was published on 2021-12-14 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:conva:fathom_analytics:*:*:*:*:*:wordpress:*:*

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