Auth bypass in Owen2345 Camaleoncms

CVE-2026-56721

CamaleonCMS version 2.9.2 and earlier contains a privilege escalation vulnerability via insecure direct object reference (IDOR) that allows authenticated low-privileged attackers to overwrite any user's credentials by exploiting a parameter confusion flaw between the authorization filter and action body in the UsersController. Attackers can send a PATCH request to the updated_ajax endpoint setting params[:id] to their own user ID to pass the self-authorization check while simultaneously setting params[:user_id] to a victim's ID, causing the controller to load and mutate the victim's account, including overwriting administrator passwords to achieve full site takeover.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (42.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.1% 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-2026-56721: held from 0.004 to 0.005.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-56721?
CVE-2026-56721 is a high-severity vulnerability in Owen2345 Camaleoncms, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.8/10. Published 2026-08-11.
How severe is CVE-2026-56721?
High severity. CVSS v3 base score is 8.8 out of 10.