Modular Connector <= 2.5.1 - Cross-Site Request Forgery via postConfirmOauth
Strategic Overview
- Status
- Patched in 2.6.0
- Affected Plugin
- Modular DS: Monitor, update, and backup multiple websites
- Affected Version
<= 2.5.1- CVSS
- 4.3Medium
- Weakness type
- CWE-352 · Cross-Site Request Forgery (CSRF)
- CVE
CVE-2026-3903
At a glance
CVE-2026-3903 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the Modular DS WordPress plugin, affecting versions <= 2.5.1. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.6.0; sites on affected versions should update now. Disclosed March 2026, reported by Dmitrii Ignatyev.
Vulnerability Overview
The Modular DS: Monitor, update, and backup multiple websites plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.5.1. This is due to missing nonce validation on the postConfirmOauth() function. This makes it possible for unauthenticated attackers to disconnect the plugin's OAuth/SSO connection via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.
CWE-352: Cross-Site Request Forgery (CSRF)
Modular DS <= 2.5.1 carries this weakness at postConfirmOauth(), and reaching it takes a caller who can reach the endpoint. Cross-site request forgery abuses the fact that browsers attach a victim's cookies to any request, so a state-changing action that only checks who you are, not whether you meant to act, can be triggered from another site.
An attacker who gets a logged-in user to load a crafted page can perform that action as them, with the impact scaling to whatever the victim's role is allowed to do. For Modular DS the fix is 2.6.0: builds <= 2.5.1 are affected, anything from 2.6.0 onward is not.
Remediation
Update to version 2.6.0, or a newer patched version
How does WordSec protect against this?
The attempt arrives as an ordinary request to Modular DS: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Modular DS 2.6.0 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
Other vulnerabilities in Modular DS: Monitor, update, and backup multiple websites
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