CVE-2026-29204: WebPros WHMCS · Insecure Direct Object Reference (IDOR)
Affects WebPros WHMCSSource CVE Database V5
Not known to be exploited · CVSS 9.1 Critical : upgrade to 18.13.3 or 9.0.4 as a priority.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 18.13.3, 9.0.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 12 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade WebPros WHMCS to 18.13.3 or 9.0.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| WebProsWHMCS | Affected
| Fixed in
|
Packagistwhmcs/whmcspkg:composer/whmcs/whmcsOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, restrict access to the client area to trusted users only and monitor for suspicious activity related to addonId parameter usage. Avoid sharing authentication credentials and consider additional application-layer access controls if possible.
Description
CVE-2026-29204 is a critical vulnerability in WebPros WHMCS affecting versions 7.4.0, 18.13.0, and 9.0.0. It involves an insecure direct object reference (IDOR) due to insufficient ownership checks in the clientarea.php component. An authenticated user can submit requests using another user's addonId without proper validation, potentially gaining unauthorized access to the victim's account.