CVE-2025-8975: Vvveb CMS Cross-Site Scripting Vulnerability

CVE-2025-8975 Overview

CVE-2025-8975 is a cross-site scripting (XSS) vulnerability affecting givanz Vvveb content management system versions up to and including 1.0.5. The flaw resides in the admin/template/content/edit.tpl file, where the slug argument is rendered without proper output encoding. An authenticated attacker can inject arbitrary JavaScript that executes in the browser of any user viewing the affected admin template. The issue is remotely exploitable over the network and has been publicly disclosed. Vvveb version 1.0.6 addresses the flaw through commit 84c11d69df8452dc378feecd17e2a62ac10dac66.

Critical Impact
Authenticated attackers can inject persistent JavaScript into the admin template editor, enabling session hijacking, credential theft, or unauthorized admin actions when other users load the affected page.

Affected Products

Vvveb CMS versions up to and including 1.0.5
The admin/template/content/edit.tpl template file
Deployments exposing the /admin interface to untrusted authenticated users

Discovery Timeline

2025-08-14 - CVE-2025-8975 published to the National Vulnerability Database
2025-08-14 - Vendor commit 84c11d69df8452dc378feecd17e2a62ac10dac66 published in Vvveb 1.0.6
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-8975

Vulnerability Analysis

The vulnerability is a stored cross-site scripting flaw classified under [CWE-79]. The affected component is the admin template rendering logic in admin/template/content/edit.tpl, which processes content placeholders of the form @@__data-v-{{type}}-content-(*)__@@. The pre-patch code echoed the value of $content[$desc] directly into HTML attributes and text nodes without invoking any encoding routine. When an attacker submits a crafted slug or name field, the raw payload is written into rendered admin pages. Any administrator or editor subsequently viewing the affected content triggers the injected script under the admin origin.

Root Cause

The root cause is missing output encoding on user-controlled fields during template rendering. The template fetched values from the $content array and emitted them with a raw echo statement. No distinction was made between the free-form content field (which legitimately contains HTML) and metadata fields such as slug or name (which should be treated as plain text). This design allowed metadata fields to inherit the trust model of the content body.

Attack Vector

Exploitation requires authenticated access with permission to create or edit content entries. The attacker submits a payload containing HTML or JavaScript in the slug parameter. Because the value is stored in the backend and rendered on subsequent admin views, the payload persists across sessions. User interaction is required from a victim administrator to load the affected admin page, at which point the injected script executes with the victim's session privileges.

text

// Patch diff - admin/template/content/edit.tpl
[data-v-{{type}}] input[data-v-{{type}}-content-*]|value = <?php
	$desc = '@@__data-v-{{type}}-content-(*)__@@';
-	if (isset($content[$desc])) 
-		echo $content[$desc];
+	if (isset($content[$desc])) {
+		if ($desc == 'content') {
+			echo $content[$desc];
+		} else {
+			echo htmlspecialchars($content[$desc]);
+		}
+	}
?>

[data-v-{{type}}] [data-v-{{type}}-content-*]|innerText = <?php
	$desc = '@@__data-v-{{type}}-content-(*)__@@';
-	if (isset($content[$desc])) 
-		echo $content[$desc];
+	if (isset($content[$desc])) {
+		if ($desc == 'content') {
+			echo $content[$desc];
+		} else {
+			echo htmlspecialchars($content[$desc]);
+		}
+	}
?>

Source: GitHub Vvveb Commit 84c11d69. The patch adds htmlspecialchars() encoding for all non-content fields while preserving raw HTML rendering for the intended content body field.

Detection Methods for CVE-2025-8975

Indicators of Compromise

Content records in the Vvveb database containing <script>, onerror=, javascript:, or HTML event handlers within the slug or name columns
Unexpected outbound HTTP requests originating from admin browser sessions to attacker-controlled domains
Admin session cookies observed in web server access logs from unfamiliar IP addresses shortly after content edits

Detection Strategies

Audit the Vvveb content database for stored fields containing angle brackets, quotes, or JavaScript keywords in slug and metadata columns
Deploy Content Security Policy (CSP) reporting to flag inline script execution attempts within the /admin path
Correlate content creation events with subsequent anomalous admin session activity through web server and application logs

Monitoring Recommendations

Log all POST requests to admin/template/content/edit endpoints with full parameter capture for forensic review
Monitor administrator account activity for privilege changes, new user creation, or content export operations that follow template edits
Enable Web Application Firewall (WAF) rules that inspect the slug parameter for XSS payload signatures

How to Mitigate CVE-2025-8975

Immediate Actions Required

Upgrade Vvveb to version 1.0.6 or later, which contains commit 84c11d69df8452dc378feecd17e2a62ac10dac66
Review all existing content entries for previously stored XSS payloads and sanitize affected records
Rotate administrator session tokens and credentials if compromise is suspected
Restrict /admin access to trusted IP ranges via network controls until patching is complete

Patch Information

The vendor released Vvveb 1.0.6 addressing this flaw. The fix, commit 84c11d69df8452dc378feecd17e2a62ac10dac66, wraps non-content fields with the PHP htmlspecialchars() function during template rendering. Refer to the Vvveb 1.0.6 Release Notes and the vendor commit for full details.

Workarounds

Apply the upstream diff manually to admin/template/content/edit.tpl if immediate upgrade is not feasible
Enforce a strict Content Security Policy on the admin interface that blocks inline scripts and restricts script sources
Limit administrative and editor privileges to a minimum set of trusted users to reduce the population of potential attackers

bash

# Upgrade Vvveb to the patched release
git fetch --tags
git checkout 1.0.6

# Verify the patched template contains htmlspecialchars protection
grep -n "htmlspecialchars" admin/template/content/edit.tpl

# Example CSP header for the admin interface (nginx)
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'" always;