Cyber Resilience

CVE-2026-29204

Critical

Published: 12 May 2026

Published
12 May 2026
Modified
13 May 2026
KEV Added
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Patch
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CVSS Score v3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0032 23.7th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-29204 is a critical-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Whmcs (inferred from references). Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 23.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability details

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.

CWE(s)
CWE-639

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Why these techniques?

CWE-639 IDOR in public-facing clientarea.php directly enables exploitation of a web app for account takeover.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-41471Shared CWE-639
CVE-2023-36331Shared CWE-639
CVE-2026-33297Shared CWE-639
CVE-2026-41084Shared CWE-639
CVE-2024-50685Shared CWE-639
CVE-2019-25235Shared CWE-639
CVE-2026-28469Shared CWE-639
CVE-2026-33511Shared CWE-639
CVE-2026-40600Shared CWE-639
CVE-2026-5396Shared CWE-639

Affected Assets

Whmcs
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inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-24 Access Control Decisions
addresses: CWE-639

Per-request decision making makes it harder to bypass authorization using user-controlled keys without proper validation in the decision process.

AC-3 Access Enforcement
addresses: CWE-639

Consistent enforcement of approved authorizations makes bypassing via user-controlled keys ineffective.

References