CVE-2016-7999 in SPIP
Summary
by MITRE
ecrire/exec/valider_xml.php in SPIP 3.1.2 and earlier allows remote attackers to conduct server side request forgery (SSRF) attacks via a URL in the var_url parameter in a valider_xml action.
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Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2016-7999 affects SPIP version 3.1.2 and earlier, specifically within the ecrire/exec/valider_xml.php script. This represents a critical server side request forgery flaw that enables remote attackers to manipulate the application's behavior by injecting malicious URLs through the var_url parameter during a valider_xml action. The vulnerability stems from insufficient input validation and sanitization of user-provided URLs, allowing attackers to redirect the application's requests to arbitrary destinations.
The technical implementation of this vulnerability occurs when the SPIP application processes XML validation requests without properly validating or filtering the URL parameter. This flaw permits attackers to craft malicious requests that can force the server to make HTTP requests to internal or external systems, potentially bypassing network security controls. The vulnerability is particularly dangerous because it can be exploited to access internal network resources that would normally be protected from external access, creating a pathway for further reconnaissance and lateral movement within the network infrastructure.
From an operational impact perspective, this vulnerability enables attackers to perform various malicious activities including internal port scanning, access to internal services, and potential data exfiltration. The SSRF attack can be leveraged to probe internal systems, access sensitive information stored on internal servers, or even facilitate more sophisticated attacks such as credential harvesting from internal services. The attack surface is particularly concerning for organizations using SPIP for content management, as it could allow attackers to gain unauthorized access to internal resources that are not directly exposed to the internet.
Security professionals should note that this vulnerability aligns with CWE-918, which specifically addresses server-side request forgery vulnerabilities in web applications. The attack pattern corresponds to techniques described in the MITRE ATT&CK framework under the T1190 technique for exploitation of remote services, and T1071 for application layer protocols. Organizations should implement immediate mitigations including input validation, URL whitelisting, and network segmentation to prevent unauthorized access to internal resources. The recommended solution involves upgrading to SPIP versions that have addressed this vulnerability, implementing proper parameter validation, and configuring network firewalls to restrict outbound connections from the application server to prevent unauthorized access to internal systems.