CVE-2026-65516 in Ultimate Invoice Plugin
Summary
by MITRE • 07/23/2026
Unauthenticated Server Side Request Forgery (SSRF) in PeproDev Ultimate Invoice <= 2.2.6 versions.
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Analysis
by VulDB Data Team • 07/23/2026
The vulnerability identified as unauthenticated server side request forgery in PeproDev Ultimate Invoice versions up to and including 2.2.6 represents a critical security flaw that allows remote attackers to make arbitrary HTTP requests from the vulnerable server. This type of vulnerability falls under the CWE-918 category, which specifically addresses Server Side Request Forgery issues where applications fail to properly validate or sanitize user input before using it in server-side operations. The flaw enables attackers to manipulate the application's behavior by injecting malicious URLs or IP addresses into parameters that are then processed by the backend server without proper authentication checks.
The technical implementation of this vulnerability occurs when the application accepts user-supplied input through various API endpoints or configuration parameters and directly uses this data in HTTP requests without adequate validation mechanisms. Attackers can exploit this by crafting specially formatted requests that cause the vulnerable server to initiate connections to internal network resources, external malicious servers, or attempt to access sensitive system components. This vulnerability is particularly dangerous because it operates entirely without requiring authentication, meaning any remote user can potentially exploit it regardless of their privileges within the application.
The operational impact of this SSRF vulnerability extends beyond simple data exfiltration and includes potential internal network reconnaissance, service enumeration, and exploitation of other vulnerabilities present within the internal infrastructure. Attackers may use this flaw to scan internal networks, access internal services that are normally protected by firewalls, or even attempt to exploit other vulnerable components within the same network environment. The vulnerability can also potentially enable attackers to perform actions such as accessing local files, performing port scans, or even executing code on the target system if additional vulnerabilities exist. This type of attack vector aligns with several techniques documented in the MITRE ATT&CK framework under the 'Server-side Request Forgery' tactic, where adversaries manipulate application behavior to achieve unauthorized access.
Mitigation strategies for this vulnerability require immediate patching of the affected software to version 2.2.7 or later, which should include proper input validation and sanitization mechanisms for all user-supplied parameters. Organizations should implement strict URL validation using allowlists of permitted domains, disable unnecessary network services, and configure proper firewall rules to restrict outbound connections from the vulnerable application. Additionally, implementing web application firewalls with SSRF protection capabilities and conducting thorough security testing including automated scanning and manual penetration testing will help identify similar vulnerabilities in other components of the system. The remediation process should also include monitoring for suspicious network activity patterns that may indicate exploitation attempts and establishing proper logging mechanisms to track all external requests made by the vulnerable application.