CVE-2025-54757: Alfasado PowerCMS RCE Vulnerability

CVE-2025-54757 Overview

CVE-2025-54757 affects multiple versions of Alfasado PowerCMS, a Japanese enterprise content management system. The vulnerability allows unrestricted upload of dangerous files [CWE-434]. A product user can upload a malicious file containing browser-executable content. If a product administrator later accesses that file, an arbitrary script executes in the administrator's browser context. The flaw combines weak upload validation with stored script execution against privileged users.

Critical Impact
An authenticated low-privilege user can upload malicious files that execute script in an administrator's browser, enabling session compromise or actions performed as the administrator.

Affected Products

Alfasado PowerCMS versions prior to 6.7.1
Alfasado PowerCMS versions prior to 5.3.1
Alfasado PowerCMS versions prior to 4.6.1

Discovery Timeline

2025-07-31 - CVE-2025-54757 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-54757

Vulnerability Analysis

The vulnerability resides in PowerCMS file upload handling. The application accepts files from authenticated users without adequately restricting file types or content. An attacker with product user credentials uploads a file crafted to be interpreted as script when rendered by a browser.

Exploitation requires user interaction from a privileged account. When a product administrator opens or previews the uploaded file through the CMS interface, the browser executes the embedded script under the CMS origin. This gives the attacker access to the administrator's authenticated session context.

The issue is classified under [CWE-434] Unrestricted Upload of File with Dangerous Type. It effectively behaves as a stored cross-site scripting vector delivered through the upload pipeline.

Root Cause

PowerCMS does not sufficiently validate uploaded file content or enforce safe content-type handling on retrieval. Files that should be treated as inert attachments can instead be served or rendered in a way that causes script execution in the viewer's browser.

Attack Vector

The attack path is network-based and requires low-privilege authentication plus victim interaction. A user-level attacker uploads the malicious file through the standard CMS upload interface. The attacker then waits for or lures an administrator to view the resource. On access, the script runs with the administrator's browser session against the PowerCMS application.

No verified public proof-of-concept exploit is available at the time of publication. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. EPSS data indicates a low near-term exploitation probability.

Detection Methods for CVE-2025-54757

Indicators of Compromise

Uploaded files in PowerCMS asset directories with executable script content, such as .html, .svg, or .htm files containing <script> tags.
Files with mismatched extensions and MIME types, or double extensions such as image.jpg.html.
Administrator sessions performing unexpected privileged actions shortly after opening user-submitted assets.

Detection Strategies

Inspect PowerCMS asset upload directories for files whose contents include HTML or JavaScript markup regardless of extension.
Review web server access logs for administrator retrievals of user-uploaded files followed by anomalous API calls from the same session.
Correlate upload events by low-privilege users with subsequent administrator content access on the same asset identifier.

Monitoring Recommendations

Monitor HTTP responses serving user-uploaded content for Content-Type: text/html or image/svg+xml originating from asset paths.
Alert on new administrator account creation, permission changes, or password resets that follow closely after asset access events.
Track outbound requests from administrator browsers to unfamiliar external domains during CMS sessions.

How to Mitigate CVE-2025-54757

Immediate Actions Required

Upgrade PowerCMS to a fixed release: 6.7.1, 5.3.1, or 4.6.1 depending on the deployed branch.
Audit existing upload directories for suspicious HTML, SVG, or script-bearing files uploaded by non-administrator accounts.
Rotate administrator credentials and invalidate active sessions if unauthorized uploads are found.

Patch Information

Alfasado has released fixed versions 6.7.1, 5.3.1, and 4.6.1. Apply the patch that corresponds to your PowerCMS branch. Details are available in the PowerCMS Release Notes and the JVN Security Vulnerability Report.

Workarounds

Restrict file upload permissions so that only trusted roles can add assets until patching is complete.
Configure the web server to serve uploaded files with Content-Type: application/octet-stream and Content-Disposition: attachment to prevent inline rendering.
Enforce a strict Content Security Policy on the PowerCMS administrative interface to block inline script execution from asset origins.
Require administrators to preview user-submitted files only in isolated browser profiles or sandboxed environments until the upgrade is applied.

bash

# Example: force download semantics for PowerCMS upload directory (Apache)
<Directory "/var/www/powercms/uploads">
    Header set Content-Disposition "attachment"
    Header set X-Content-Type-Options "nosniff"
    <FilesMatch "\.(html?|svg|xml|js)$">
        ForceType application/octet-stream
    </FilesMatch>
</Directory>