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The vulnerability stems from insufficient input validation within the Ghost Content Management System, specifically inside the internal file processing components like the `ImageSize` service. When an authenticated staff member interacts with endpoints that process server-side files, user-supplied relative path strings are passed directly into filesystem utility functions without proper path canonicalization or strict containment checks. As a consequence, directory traversal sequences such as `../` escape the designated root storage directories (e.g., /content/images/). An attacker leveraging staff-level credentials can craft requests targeting arbitrary local files present on the host operating system, leading to unauthorized local file access and sensitive data disclosure across host server directories.
DailyCVE Form:
Platform: Ghost CMS
Version: 6.14.0 – 6.26.0
Vulnerability: Path Traversal LFI
Severity: Medium
date: 2026-09-30
Prediction: Already Patched (v6.27.0)
What Undercode Say:
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The vulnerability highlights common pitfalls in file-handling functions within Node.js applications. Insufficient path sanitization in administrative file-processing logic allows relative paths to bypass basic prefix validation.
Update Ghost-CLI installation to patched version ghost update 6.27.0 Verify installed Ghost version ghost version Docker update workflow docker pull ghost:6.27.0 docker stop ghost_app docker run -d --name ghost_app -p 2368:2368 ghost:6.27.0
// Conceptual representation of vulnerable file path resolution
const path = require('path');
const fs = require('fs');
function getLocalImageDimensions(userInputPath) {
// Vulnerable: Direct concatenation without canonicalization checks
const targetPath = path.join('/var/www/ghost/content/images/', userInputPath);
return fs.readFileSync(targetPath);
}
// Fixed implementation using path canonicalization validation
function getLocalImageDimensionsFixed(userInputPath) {
const baseDir = path.resolve('/var/www/ghost/content/images/');
const resolvedPath = path.resolve(baseDir, userInputPath);
if (!resolvedPath.startsWith(baseDir)) {
throw new Error('Access denied: Unauthorized directory traversal attempt.');
}
return fs.readFileSync(resolvedPath);
}
Exploit: (Educational Purposes!)
An authenticated staff user transmits a request manipulating image paths to traverse directories and read local files:
GET /ghost/api/admin/images/size/?path=../../../../etc/passwd HTTP/1.1 Host: target-ghost-instance.com Authorization: Bearer <STAFF_JWT_TOKEN> User-Agent: Mozilla/5.0
Protection: from this CVE
Upgrading Ghost CMS to version 6.27.0 or higher resolves the path traversal vulnerability. Restrict staff user permissions to enforce least privilege principles, and run Node.js processes under a low-privileged system user limited to the application directory.
Impact
Allowed staff-level users to read arbitrary local files outside intended data storage directories on the host server.
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Sources:
Reported By: github.com
Extra Source Hub:
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