WebPros WHMCS up to 8.12.2/8.13.2/9.0.3 clientarea.php addonId authorization

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.5$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in WebPros WHMCS up to 8.12.2/8.13.2/9.0.3. This issue affects some unknown processing of the file clientarea.php. Executing a manipulation of the argument addonId can lead to authorization. This vulnerability appears as CVE-2026-29204. The attack may be performed from remote. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical was found in WebPros WHMCS up to 8.12.2/8.13.2/9.0.3. This vulnerability affects an unknown part of the file clientarea.php. The manipulation of the argument addonId with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Insufficient ownership checks in `clientarea.php` allow 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 resources and their cPanel account.

The advisory is shared for download at help.whmcs.com. This vulnerability was named CVE-2026-29204 since 03/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

By approaching the search of inurl:clientarea.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 8.13.3 or 9.0.4 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.6
VulDB Meta Temp Score: 8.5

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 10.0
CNA Vector (hackerone): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-639 / CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Google Hack: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: WHMCS 8.13.3/9.0.4

Timelineinfo

03/04/2026 CVE reserved
05/12/2026 +68 days Advisory disclosed
05/12/2026 +0 days VulDB entry created
05/12/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: help.whmcs.com
Status: Confirmed

CVE: CVE-2026-29204 (🔒)
GCVE (CVE): GCVE-0-2026-29204
GCVE (VulDB): GCVE-100-363268

Entryinfo

Created: 05/12/2026 20:38
Changes: 05/12/2026 20:38 (64)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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