CVE-2026-40500
CWE-918Published: April 15, 2026· Updated: Apr 17, 2026
Official Description
ProcessWire CMS version 3.0.255 and prior contain a server-side request forgery vulnerability in the admin panel's 'Add Module From URL' feature that allows authenticated administrators to supply arbitrary URLs to the module download parameter, causing the server to issue outbound HTTP requests to attacker-controlled internal or external hosts. Attackers can exploit differentiable error messages returned by the server to perform reliable internal network port scanning, host enumeration across RFC-1918 ranges, and potential access to cloud instance metadata endpoints.
Technical Analysis
CVE-2026-40500 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires high privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 6.8.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (3)
Quick Facts
Related CVEs (CWE-918)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-40500 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts