medium CVSS 6.1

CVE-2026-33035·PHP vulnerability

WWBN AVideo is an open source video platform. In versions 25.0 and below, there is a reflected XSS vulnerability that allows unauthenticated attackers to execute arbitrary JavaScript in a victim's browser. User input from a URL parameter flows through PHP's json_encode() into a JavaScript function that renders it via innerHTML, bypassing encoding and achieving full script execution. The vulnerability is caused by two issues working together: unescaped user input passed to JavaScript (videoNotFound.php), and innerHTML rendering HTML tags as executable DOM (script.js). The attack can be escalated to steal session cookies, take over accounts, phish credentials via injected login forms, spread self-propagating payloads, and compromise admin accounts — all by exploiting the lack of proper input sanitization and cookie security (e.g., missing HttpOnly flag on PHPSESSID). The issue has been fixed in version 26.0.

Severity
medium
Software
PHP
Fixed in
26.0
Published
2026-03-20

Affected versions

Until: 26.0

Fixed in: 26.0

How to fix this CVE

Upgrade PHP to version 26.0 or later to patch the reflected XSS vulnerability in the AVideo platform. This fix addresses improper handling of user input in URL parameters that could allow attackers to inject and execute malicious JavaScript. Ensure your web application framework and all dependent packages are also updated to the latest stable versions.

sudo dnf update php

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

GET|POST.*(?:videoNotFound\.php|video_not_found).*(?:v=|video=|id=).*(?:<script|javascript:|onerror=|onclick=|on\w+\s*=|%3Cscript|%22onclick|%27onclick)

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Block or sanitize URL parameters passed to videoNotFound.php that contain script tags, event handlers (onerror, onclick, onload, etc.), or JavaScript protocol schemes. Implement a WAF rule to reject requests matching: <script, javascript:, event handlers, and HTML entity-encoded variants. Additionally, enforce Content-Security-Policy (CSP) headers with script-src 'self' to prevent inline script execution.

How to check if you are affected

  1. Check installed PHP version: php -v
  2. Identify if AVideo platform is deployed: grep -r 'videoNotFound.php' /var/www/ || find / -name 'videoNotFound.php' 2>/dev/null
  3. Search web server access logs for suspicious URL parameters containing script tags or encoded payloads: grep -E '(script|onerror|onclick|javascript:)' /var/log/apache2/access.log /var/log/nginx/access.log
  4. Verify the fix by checking PHP version matches 26.0 or higher: php -v | grep -E '(26\.|27\.|[3-9][0-9]\.)'

FAQ

What is CVE-2026-33035?

CVE-2026-33035 is a reflected cross-site scripting (XSS) vulnerability in AVideo versions 25.0 and below that allows attackers to inject malicious JavaScript code through unvalidated URL parameters, which are then rendered in the victim's browser without proper sanitization.

Is CVE-2026-33035 being actively exploited?

No, CVE-2026-33035 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, and no public exploits are available, though the attack vector is straightforward and organizations should remediate proactively.

What versions of PHP are affected by CVE-2026-33035?

AVideo versions 25.0 and below are vulnerable; the vulnerability has been fixed in version 26.0. The issue affects PHP deployments running affected AVideo releases.

How do I check if my server is vulnerable to CVE-2026-33035?

Run 'php -v' to check your PHP version, then verify AVideo version with 'grep -r "AVIDEO_VERSION" /path/to/avideo/' or check the application dashboard. If AVideo is version 25.0 or below, your installation is vulnerable.

Does Defensia detect CVE-2026-33035?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If PHP is installed on a monitored server, CVE-2026-33035 will appear in your dashboard with remediation steps.

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References

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