CVE-2026-70593 in Ghost
Summary
by MITRE • 08/05/2026
Ghost is a Node.js content management system. From 0.10.0 until 6.54.1, a vulnerability in custom themes allowed a staff user to write files outside of the uploads directory. This could be used to alter the behavior of the installation through custom theme upload path traversal in LocalStorageBase and theme storage name handling. This issue is fixed in version 6.54.1.
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Analysis
by VulDB Data Team • 08/05/2026
The Ghost content management system presents a critical path traversal vulnerability affecting versions 0.10.0 through 6.54.1 that stems from inadequate input validation in the custom theme upload functionality. This flaw specifically manifests in the LocalStorageBase component and theme storage name handling mechanisms where user-supplied data fails to properly sanitize file paths before being processed. The vulnerability enables authenticated staff users with sufficient privileges to exploit a directory traversal attack by manipulating theme upload paths, allowing them to write files beyond the designated uploads directory boundaries.
The technical implementation of this vulnerability resides in how Ghost handles theme storage names and path resolution during custom theme installations. When staff members upload custom themes, the system processes the provided theme name without adequate validation of special characters or directory navigation sequences such as double dots or forward slashes that could manipulate the intended file destination. This weakness operates under CWE-22 Path Traversal vulnerability classification where insufficient input sanitization allows attackers to access files outside the intended directory structure through crafted path inputs.
The operational impact of this vulnerability extends beyond simple file system manipulation as it provides a potential attack vector for privilege escalation and persistent backdoor establishment within Ghost installations. An attacker with staff-level access could leverage this vulnerability to overwrite critical system files, inject malicious code into theme templates, or modify core application components that would alter the behavior of the entire installation. The LocalStorageBase component's handling of theme storage names creates a direct pathway for arbitrary file creation and modification outside the normal upload sandbox, potentially compromising the integrity and availability of the content management environment.
Security professionals should note this vulnerability aligns with ATT&CK technique T1059.006 Command and Scripting Interpreter: PowerShell where attackers could leverage path traversal to execute malicious code through compromised theme files. The fix implemented in version 6.54.1 addresses the core issue by introducing proper input validation and path sanitization routines that prevent directory traversal sequences from being processed as legitimate file paths during theme uploads. Organizations should immediately upgrade to version 6.54.1 or later to remediate this vulnerability, while also implementing additional monitoring for unauthorized theme uploads and file system modifications in their Ghost installations. The mitigation strategy must include comprehensive input validation at all points where user-supplied data influences file system operations, particularly within content management systems that handle user-generated themes or plugins.