CVE-2021-41836 json
Fathom Analytics <= 3.0.4 Authenticated Stored Cross-Site Scripting
published 2021-12-14 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-28837
- cvss
- 4.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 48%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 20 mo ago
Exploit prediction
0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 3.5 | AV:N/AC:M/Au:S/C:N/I:P/A:N |
Affected products
- Fathom Analytics Fathom Analytics
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
-
plugins.trac.wordpress.org
/changeset?sfp_email=&sfph_mail=&reponame=&old=2641005%40fathom-analytics&new=2641005%40fathom-analytics&sfp_e
patch, third-party-advisory
-
wordfence.com
/vulnerability-advisories/#CVE-2021-41836
third-party-advisory
Sources
- CVE List CVE-2021-41836
- NVD CVE-2021-41836
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.