CVE-2025-54543: Opensolution Quick.cms XSS Vulnerability

CVE-2025-54543 Overview

CVE-2025-54543 is a Stored Cross-Site Scripting (XSS) vulnerability in OpenSolution Quick.CMS version 6.8. The flaw resides in the sDescriptionMeta parameter within the page editor's SEO functionality. An authenticated administrator can inject arbitrary HTML and JavaScript, which executes when users visit the affected page. By default, admin users are not permitted to inject JavaScript into the site, so this behavior violates the application's security model. The vendor was notified but did not respond with details about the vulnerable version range. Only version 6.8 has been confirmed vulnerable, though other versions may also be affected. The weakness is classified as [CWE-79].

Critical Impact
Attackers with admin privileges can inject persistent JavaScript through the SEO metadata field, bypassing the application's restriction against admin-added scripts and executing code in visitors' browsers.

Affected Products

OpenSolution Quick.CMS 6.8 (confirmed vulnerable)
Other Quick.CMS versions (untested, potentially vulnerable)
Deployments exposing the page editor SEO functionality to admin users

Discovery Timeline

2025-08-28 - CVE-2025-54543 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-54543

Vulnerability Analysis

Quick.CMS provides a page editor that includes SEO metadata fields, one of which is sDescriptionMeta. This field is intended to store plain text used for the HTML <meta name="description"> tag. The application fails to sanitize or encode the input, allowing arbitrary HTML and JavaScript to be stored and later rendered in the response. When a visitor loads the edited page, the injected payload executes in the browser under the site's origin. This constitutes a stored XSS condition [CWE-79] persisted through the administrative interface.

The vulnerability is notable because Quick.CMS's design explicitly prevents administrators from adding JavaScript through normal content-authoring paths. The sDescriptionMeta handler bypasses that restriction, providing an unintended script-injection vector for any account with editor privileges.

Root Cause

The root cause is missing output encoding and input validation on the sDescriptionMeta parameter processed by the page editor's SEO functionality. User-supplied content is written into the rendered page without HTML-entity encoding, allowing tag and script content to be interpreted by the browser.

Attack Vector

Exploitation requires an authenticated administrator account and user interaction from a subsequent visitor to the edited page. The attacker submits a malicious HTML or JavaScript payload through the SEO description field in the page editor. The payload is stored in the CMS backend and served to every visitor who requests the affected page. Consequences include session token theft, forced browser actions against other users, defacement, and phishing pivots targeting site visitors. See the CERT Poland blog post for context on related Quick.CMS disclosures and the OpenSolution resource page for product information.

Detection Methods for CVE-2025-54543

Indicators of Compromise

Unexpected <script>, <img onerror=...>, or event-handler markup rendered inside <meta name="description"> tags on public pages
Audit-log entries showing edits to the sDescriptionMeta field by unfamiliar or recently created admin accounts
Outbound requests from visitor browsers to attacker-controlled hosts referred from Quick.CMS pages

Detection Strategies

Inspect page source for HTML metadata fields containing angle brackets, encoded scripts, or JavaScript URI schemes
Review database records for the sDescriptionMeta column and flag entries containing HTML control characters
Correlate administrative edit events with subsequent user-agent anomalies or credential resets

Monitoring Recommendations

Alert on admin logins from new geographies or unrecognized IP addresses accessing the page editor
Deploy a web application firewall rule set to log HTML markup submitted to SEO metadata parameters
Enable and centrally forward Quick.CMS admin audit logs to a SIEM for retention and analysis

How to Mitigate CVE-2025-54543

Immediate Actions Required

Audit all Quick.CMS pages for existing content in sDescriptionMeta and remove any entries containing HTML tags or script content
Restrict administrative access to the CMS backend using IP allowlists and multi-factor authentication
Rotate credentials for all administrator accounts and review recent admin activity for unauthorized edits

Patch Information

No vendor patch has been published for CVE-2025-54543 at the time of NVD publication. According to the disclosure, OpenSolution did not respond with details about a vulnerable version range or fix availability. Monitor the OpenSolution website for updated releases and apply them once available.

Workarounds

Implement a strict Content Security Policy (CSP) that disallows inline scripts and restricts script sources to trusted origins
Front the Quick.CMS deployment with a WAF rule that strips or blocks HTML tags submitted to the sDescriptionMeta field
Limit page-editor access to a minimal set of trusted administrators until a vendor fix is released

bash

# Example NGINX Content-Security-Policy header to reduce stored XSS impact
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'" always;