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high advisory

Vvveb CMS XML External Entity Injection Vulnerability

Vvveb before 1.0.8.2 is vulnerable to XML external entity (XXE) injection in the admin import feature, allowing authenticated site administrators to read arbitrary files and modify database records, potentially leading to privilege escalation.

Vvveb, a content management system, is susceptible to an XML External Entity (XXE) injection vulnerability (CVE-2026-41936) affecting versions prior to 1.0.8.2. The vulnerability resides in the admin Tools/Import functionality, specifically within the system/import/xml.php file. Authenticated users with site_admin privileges can exploit this flaw to inject malicious XML payloads containing file:// or php://filter entity references. This allows attackers to read arbitrary files from the server, including sensitive configuration files and application source code. Furthermore, successful exploitation can lead to the modification of database records, potentially enabling administrator password hash overwriting for privilege escalation, and gaining complete control over the CMS. This vulnerability poses a significant risk to organizations using Vvveb for managing their websites, as it allows unauthorized access to sensitive data and system compromise.

Attack Chain

  1. An attacker authenticates to the Vvveb CMS as a site administrator.
  2. The attacker navigates to the admin Tools/Import section.
  3. The attacker crafts a malicious XML file containing an XXE payload with a file:// or php://filter wrapper.
  4. The malicious XML payload is uploaded through the import feature.
  5. The Vvveb application parses the XML file using the vulnerable system/import/xml.php script.
  6. The XML parser resolves the external entities, reading arbitrary files from the system.
  7. The application then persists the resolved entities into the application database.
  8. The attacker leverages database modification to overwrite the administrator password hash, gaining elevated privileges.

Impact

Successful exploitation of this XXE vulnerability can have severe consequences. An attacker can read sensitive files from the server, potentially exposing confidential data, source code, and API keys. More critically, the ability to modify database records allows for administrator password hash overwriting, leading to complete compromise of the Vvveb CMS. There is no mention of victim count or sector targeting in the source material.

Recommendation

  • Upgrade Vvveb to version 1.0.8.2 or later to patch CVE-2026-41936.
  • Deploy the Sigma rule to detect exploitation attempts against the system/import/xml.php endpoint in Vvveb.
  • Implement strict input validation and sanitization for XML files uploaded through the admin interface to prevent XXE attacks.

Detection coverage 2

Detect Vvveb XXE Injection Attempt via Import Functionality

high

Detects attempts to exploit the XXE vulnerability in Vvveb's import functionality by monitoring for requests to the xml.php endpoint with suspicious XML content.

sigma tactics: initial_access, privilege_escalation techniques: T1190 sources: webserver, linux

Detect Vvveb Database Modification via XML Import

critical

Detects attempts to modify the Vvveb database by importing an XML file with a payload designed to alter sensitive data, such as administrator password hashes.

sigma tactics: credential_access, persistence techniques: T1003 sources: webserver, linux

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