CVE-2026-23698 in Vtiger
Summary
by MITRE • 07/07/2026
Vtiger CRM through 8.4.0 contains an authenticated remote code execution vulnerability in the admin module import feature that allows administrator-level attackers to upload arbitrary PHP files by submitting a crafted zip archive through the ModuleManager import function, which extracts contents directly into the modules/ directory under the web root without validating file types beyond the manifest.xml descriptor. Attackers can place executable PHP files in the modules/ directory that become directly accessible via HTTP, bypassing Vtiger's authentication and authorization layer entirely since Apache resolves the path and invokes the PHP interpreter before the application routing layer is involved, resulting in a persistent web shell independent of the originating session.
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Analysis
by VulDB Data Team • 07/07/2026
This vulnerability represents a critical security flaw in Vtiger CRM versions up to 8.4.0 that stems from inadequate input validation during the module import process within the administrative interface. The issue manifests through the ModuleManager import function which accepts zip archives containing module definitions and automatically extracts their contents directly into the web root's modules/ directory without proper file type verification beyond the manifest.xml descriptor. This design flaw creates a path traversal and code execution vulnerability that fundamentally undermines the application's security model.
The technical exploitation of this vulnerability occurs when an authenticated administrator user uploads a maliciously crafted zip archive containing PHP files that are extracted directly into the modules/ directory where they become immediately accessible via standard HTTP requests. The vulnerability leverages the fact that Apache processes PHP files automatically before the Vtiger application's routing layer can enforce authentication checks, effectively bypassing all session-based security controls. This creates a persistent backdoor that remains active regardless of user sessions or subsequent authentication attempts, as the PHP files are executed directly by the web server without any application-level authorization verification.
From an operational perspective, this vulnerability presents a severe risk to organizations using Vtiger CRM since it allows attackers with administrative credentials to establish persistent access to the system. The attack vector requires only administrative login privileges which, when compromised through credential theft or social engineering, provides immediate code execution capabilities. The persistent nature of the web shell means that even if administrators change passwords or revoke sessions, the malicious PHP files remain accessible and executable, creating a long-term security threat that can persist across system restarts and application updates.
The vulnerability maps directly to CWE-434 which describes insecure file upload vulnerabilities where applications accept untrusted files without proper validation. Additionally, this flaw aligns with ATT&CK technique T1505.003 for "Download and Execute" and T1078.004 for "Valid Accounts" since it requires administrative credentials but then bypasses authentication entirely once the malicious payload is deployed. Organizations should implement immediate mitigations including restricting write permissions on the modules/ directory, implementing strict file type validation for all uploaded archives, and monitoring for unauthorized file modifications in critical directories. The most effective long-term solution involves updating to patched versions of Vtiger CRM where proper input validation has been implemented in the module import functionality, preventing arbitrary file extraction into web-accessible locations while maintaining legitimate module installation capabilities.