CVE-2026-56661

Summary

The GetSimple CMS update handler is vulnerable to Server-Side Request Forgery (SSRF) due to insufficient validation of user-supplied URLs. An attacker can make the server fetch content from arbitrary destinations including internal services and cloud metadata endpoints, potentially leading to information disclosure.

Exploitability

Exploitation requires a user with access to the update handler form, which is typically a low-privilege account. The attack is relatively straightforward once the precondition is met.

Blast radius

If exploited, this vulnerability could allow attackers to read internal system files, cloud metadata, and potentially other sensitive data from internal services accessible to the web server.

Detection

Monitor for unusual file creation patterns in the /Tmpfile.zip directory, particularly when accessed by the CMS update handler process, and watch for outbound network requests to internal IP ranges like 169.254.169.254 or other internal services.

Prioritized remediation

Upgrade to version 1.5 or later to patch the SSRF vulnerability in the update handler.

Analysis generated locally by garnet-coder (no data left the box). AI-assisted — verify against primary sources before acting.