CVE-2026-56661

GetSimple CMS: Server-Side Request Forgery in the UpdateCE update endpoint

HIGH
7.5
CVSS Score
Published: October 1, 2026 at 07:38 PM UTC
Updated: October 1, 2026 at 08:23 PM UTC
1 product affected across 1 vendorGetSimpleCMS-CE

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

GetSimple CMS is a content management system (CMS), and GetSimple CMS CE is the community edition of that CMS. Prior to version 1.5, the update handler fetches a user-supplied URL with file_get_contents() after only format validation (FILTER_VALIDATE_URL) — there is no validation of the request destination. An attacker who can submit the form can make the server issue requests to arbitrary destinations, including internal-only services and cloud metadata endpoints (169.254.169.254). The fetched response body is written to a web-accessible file (/Tmpfile.zip) and is not deleted when the content is not a valid ZIP, turning this into a full-read SSRF: the attacker can retrieve the response of the internal request directly. This issue has been patched in version 1.5.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.5
Affected range stops below 1.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-918

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