CVE-2021-4074 json
WHMCS Bridge <= 6.1 Subscriber+ Stored Cross-Site Scripting
published 4y ago modified 4mo ago also EUVD-2021-33967
- cvss
- 6.4
- 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 46%
- public exploits
- 0
- none known
Summary
The WHMCS Bridge WordPress plugin is vulnerable to Stored Cross-Site Scripting via the cc_whmcs_bridge_url parameter found in the ~/whmcs-bridge/bridge_cp.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 6.1. Due to missing authorization checks on the cc_whmcs_bridge_add_admin function, low-level authenticated users such as subscribers can exploit this vulnerability.
Patch / fix
Is CVE-2021-4074 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- last yr.
Exploit prediction
0.56% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| NVD | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/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
- WHMCS Bridge WHMCS Bridge
Classification
- Weakness
- Technology feeds
References
-
plugins.trac.wordpress.org
/changeset?sfp_email=&sfph_mail=&reponame=&old=2653041%40whmcs-bridge&new=2653041%40whmcs-bridge&sfp_email=&sf
issue-tracking, patch, third-party-advisory
-
wordfence.com
/vulnerability-advisories/#CVE-2021-4074
third-party-advisory
Sources
- CVE List CVE-2021-4074
- NVD CVE-2021-4074
Fencer Intel 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.