Simple Google Calendar Outlook Events Widget <= 3.0.0 - Unauthenticated Server-Side Request Forgery
Strategic Overview
- Status
- Patched in 3.1.0
- Affected Plugin
- Simple Google Calendar Outlook Events Widget
- Affected Version
<= 3.0.0- CVSS
- 7.2High
- Weakness type
- CWE-918 · Server-Side Request Forgery (SSRF)
- CVE
CVE-2026-16536
At a glance
CVE-2026-16536 is a high-severity Server-Side Request Forgery (SSRF) vulnerability in the Simple Google Calendar Outlook Events Widget WordPress plugin, affecting versions <= 3.0.0. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.1.0; sites on affected versions should update now. Disclosed July 2026, reported by Pablo González Pérez.
Vulnerability Overview
The Simple Google Calendar Outlook Events Widget plugin for WordPress is vulnerable to Server-Side Request Forgery in versions up to, and including, 3.0.0. This is due to missing whitelist validation on REST request parameters, allowing calendar_id to be passed directly as a block attribute and trigger arbitrary URL fetches. This makes it possible for unauthenticated attackers to make server-side HTTP requests to arbitrary locations by supplying a calendar_id parameter to the REST endpoint, causing the server to fetch attacker-controlled URLs.
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, and no interaction from a victim user.
CWE-918: Server-Side Request Forgery (SSRF)
Reaching this weakness in Simple Google Calendar Outlook Events Widget <= 3.0.0 takes no account at all. Server-side request forgery means the application fetches a URL supplied by the caller, turning the server into a proxy for requests the attacker could not make directly.
The request originates from inside the hosting network, which is how these flaws reach cloud metadata endpoints, internal admin panels and services that trust local traffic. For Simple Google Calendar Outlook Events Widget the fix is 3.1.0: builds <= 3.0.0 are affected, anything from 3.1.0 onward is not.
Remediation
Update to version 3.1.0, or a newer patched version
How does WordSec protect against this?
Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Simple Google Calendar Outlook Events Widget 3.1.0 closes this, and updating the plugin is the step that ends it.
- Firewall
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in Simple Google Calendar Outlook Events Widget
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C