CVE-2026-39521
Server-Side Request Forgery in Nelio Content
Publication date: 2026-04-08
Last updated on: 2026-04-13
Assigner: Patchstack
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| nelio_software | nelio_content | to 4.3.1 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-918 | The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-39521 is a Server Side Request Forgery (SSRF) vulnerability in the Nelio Content WordPress plugin versions up to and including 4.3.1.
This vulnerability allows a malicious actor with contributor or developer privileges to make the affected website send HTTP requests to arbitrary domains controlled by the attacker.
By exploiting this flaw, the attacker could potentially access sensitive information from other services running on the same system.
How can this vulnerability impact me? :
Exploiting this SSRF vulnerability could allow an attacker to make unauthorized server-side requests to attacker-controlled domains.
This may lead to exposure of sensitive internal services or information hosted on the same system as the vulnerable plugin.
Although the CVSS severity score is 4.9 (low severity), such vulnerabilities are often targeted in mass-exploit campaigns affecting many websites.
To mitigate the risk, it is strongly advised to update the Nelio Content plugin to version 4.3.2 or later where the vulnerability is patched.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability allows an attacker with contributor or developer privileges to cause the affected website to make HTTP requests to arbitrary attacker-controlled domains. Detection can involve monitoring outgoing HTTP requests from the server to unusual or unexpected external domains.
Specific commands or tools to detect this vulnerability are not provided in the available resources.
What immediate steps should I take to mitigate this vulnerability?
The immediate mitigation step is to update the Nelio Content Plugin to version 4.3.2 or later, where this SSRF vulnerability is patched.
Users are strongly advised to apply this update promptly to prevent exploitation.
Additionally, Patchstack offers automated updates for vulnerable plugins to facilitate rapid mitigation.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
CVE-2026-39521 is a Server Side Request Forgery (SSRF) vulnerability that allows an attacker to make unauthorized HTTP requests to arbitrary domains, potentially exposing sensitive internal services and information.
While the vulnerability has a low severity score (CVSS 4.9), exploitation could lead to unauthorized access to sensitive data, which may impact compliance with data protection regulations such as GDPR or HIPAA if personal or protected health information is exposed.
Therefore, organizations using affected versions of the Nelio Content Plugin should promptly apply the patch (version 4.3.2 or later) to mitigate risks that could lead to non-compliance with these standards.