CVE-2021-4074WHMCS Bridge <= 6.1 Subscriber+ Stored Cross-Site Scripting
- 6.4MediumCVSS base score
- 0.58%Exploitation in 30 daysEPSS · top 52% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Wordfence
- 43 days later
· 43 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| WordfenceCNA (assigner) | 3.1 | Medium6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.58% · top 52% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.4.
Affected products
- affected 6.1 – ≤ 6.1
What to do
Solution: Update to version 6.3, or newer.
References
References2
- https://www.wordfence.com/vulnerability-advisories/#CVE-2021-4074 (opens in a new tab)x_refsource_MISCx_transferred
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2653041%40whmcs-bridge&new=2653041%40whmcs-bridge&sfp_email=&sfph_mail= (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-33967 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-4074)Record last updated .