CVE-2021-4074: WHMCS Bridge <= 6.1 Subscriber+ Stored Cross-Site Scripting

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-01-18 · updated 2026-06-17
Weakness: CWE-79

Description

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.

Affected products

WHMCS Bridge: through 6.1

References

https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2653041%40whmcs-bridge&new=2653041%40whmcs-bridge&sfp_email=&sfph_mail=
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-4074
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2653041%40whmcs-bridge&new=2653041%40whmcs-bridge&sfp_email=&sfph_mail=
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-4074

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