Auth bypass in Webpros Whmcs

CVE-2026-29204

Insufficient ownership check in `clientarea.php` allows an authenticated client area user to submit requests using another user’s `addonId` without any ownership validation leading to unauthorized access to the victim's account.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (24.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-29204: held from 0.005 to 0.003.

EPSS over last 30 days · oldest: 0.005 · newest: 0.003 · change: -0.001

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-29204?
CVE-2026-29204 is a critical-severity vulnerability in Webpros Whmcs, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 9.1/10. Published 2026-05-12.
How severe is CVE-2026-29204?
Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2026-29204 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.