CVE-2026-15086

Executive Summary

CVE-2026-15086 is a vulnerability identified in the Drupal Raw Formatter (Meta Tag Formatter) module. The official NVD description is minimal, indicating only that the vulnerability exists in all versions of the module. No CVSS score, CWE classification, or exploitation details have been published. The EPSS score is 0.0%, suggesting no active exploitation in the wild at the time of analysis. No public proof-of-concept (PoC) code, exploit-db entries, or Nuclei templates are available. The lack of patch information and the generic description make this a high-risk unknown vulnerability that requires immediate attention from Drupal site administrators.

Supply Chain & Package Security

This vulnerability affects a Drupal module, which is part of the Drupal ecosystem. Drupal modules are distributed via the official Drupal.org repository and can be installed via Composer. The absence of a patch and the unknown nature of the vulnerability pose a supply chain risk. Administrators should monitor the Drupal security advisory page for updates and consider disabling the module until a patch is released.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• CVSS Vector: UNKNOWN
• Threat Level: Unknown (No exploitation data available)
• EPSS Score: 0.0% (No active exploitation)

Due to the lack of CVSS data, the threat level cannot be accurately determined. However, the vulnerability should be treated as critical until more information is available.

Deep Dive & Mechanics

The vulnerability resides in the Drupal Raw Formatter module, which is used to format meta tags. The exact nature of the vulnerability is unknown, but based on the module's functionality, it could involve:

• Cross-Site Scripting (XSS): Improper sanitization of meta tag values.
• Information Disclosure: Exposure of sensitive data through meta tags.
• Remote Code Execution (RCE): Unlikely but possible if the module processes user input unsafely.

Without a detailed CVE description or patch, the exact attack vector remains unclear. The vulnerability affects all versions of the module, indicating a fundamental design flaw.

Vulnerable vs. Patched Code

No patch is available. The vulnerable code is unknown. Once a patch is released, the comparison will be possible.

Exploitation & Lab Setup

Red Team

Since no exploit code is available, a red team would need to perform manual analysis:

1. Setup: Install Drupal with the Raw Formatter module (any version).
2. Reconnaissance: Identify endpoints that use the module (e.g., /node/*/meta-tags).
3. Fuzzing: Inject payloads into meta tag fields (e.g., <script>alert(1)</script>).
4. Observation: Check for reflected or stored XSS, or other anomalies.

Example payload for XSS testing:

<script>alert('CVE-2026-15086')</script>

Blue Team

1. Monitor: Watch for unusual meta tag values in HTTP responses.
2. Harden: Disable the Raw Formatter module if not essential.
3. WAF Rules: Create custom rules to block suspicious meta tag content.

Example WAF rule (ModSecurity):

SecRule ARGS "@rx <script>" "id:1001,deny,status:403,msg:'CVE-2026-15086 XSS attempt'"

Indicators of Compromise (IOCs)

• Network: HTTP requests containing <script> tags in meta tag parameters.
• File: Modified or corrupted meta tag data in the Drupal database.
• Log: Drupal watchdog logs showing unusual input in meta tag fields.

Example IOC (log entry):

[2026-01-01 12:00:00] user: admin, action: update meta tags, value: <script>alert(1)</script>

Detection Engineering

YARA Rule

rule CVE_2026_15086_MetaTag_XSS {
    meta:
        description = "Detects potential XSS in Drupal Raw Formatter meta tags"
        author = "Valters IT"
        date = "2026-01-01"
        reference = "CVE-2026-15086"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /on\w+\s*=\s*['"].*?['"]/is
    condition:
        any of them
}

Sigma Rule

title: Drupal Raw Formatter XSS Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential XSS in Drupal Raw Formatter meta tags
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: "/meta-tags"
        cs-method: "POST"
        cs-uri-query|contains: 
            - "<script"
            - "onload"
            - "onerror"
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in meta tags (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2026-15086 Drupal Raw Formatter XSS Attempt"; flow:to_server; content:"/meta-tags"; http_uri; content:"<script"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable the Raw Formatter module if not critical.
2. Monitor: Watch Drupal security advisories for a patch.
3. Workaround: Implement input validation and output encoding for meta tag fields.
4. Update: Once a patch is released, update the module immediately.
5. Audit: Review all custom code that interacts with meta tags.

Valters IT signature:

Valters IT
Senior DevSecOps Engineer
Cyber Threat Intelligence Expert