Nelio Content <= 4.3.1 - Authenticated (Contributor+) Server-Side Request Forgery
Strategic Overview
- Status
- Patched in 4.3.2
- Affected Version
<= 4.3.1- CVSS
- 6.4Medium
- Weakness type
- CWE-918 · Server-Side Request Forgery (SSRF)
- CVE
CVE-2026-39521
At a glance
CVE-2026-39521 is a medium-severity Server-Side Request Forgery (SSRF) vulnerability in the Nelio Content WordPress plugin, affecting versions <= 4.3.1. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 4.3.2; sites on affected versions should update now. Disclosed March 2026, reported by Steven Julian.
Vulnerability Overview
The Nelio Content – Editorial Calendar & Social Media Auto-Posting plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 4.3.1. This makes it possible for authenticated attackers, with Contributor-level access and above, to make web requests to arbitrary locations originating from the web application which can be used to query and modify information from internal services.
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 interaction from a victim user.
CWE-918: Server-Side Request Forgery (SSRF)
Reaching this weakness in Nelio Content <= 4.3.1 takes an account at Contributor level or above. 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 Nelio Content the fix is 4.3.2: builds <= 4.3.1 are affected, anything from 4.3.2 onward is not.
Remediation
Update to version 4.3.2, or a newer patched version
How does WordSec protect against this?
An attacker needs Contributor access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Nelio Content 4.3.2 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in Nelio Content – Editorial Calendar & Social Media Auto-Posting
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