CVE-2025-66956 is a critical security vulnerability identified in Asseco SEE Live 2.0, specifically affecting its Contact Plan, E-Mail, SMS, and Fax components. The root cause is insecure access control (CWE-284), which allows remote attackers to bypass intended access restrictions and gain unauthorized access to attachments. These attachments can then be executed remotely via a computable URL, meaning an attacker can craft or derive a URL that triggers execution without requiring user interaction. The vulnerability has a CVSS v3.1 base score of 9.9, indicating critical severity with network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), and scope changed (S:C), impacting confidentiality, integrity, and availability at a high level (C:H/I:H/A:H). The exploitability is high due to the lack of user interaction and low complexity, although some privileges are required, which could be obtained through other means or insider threats. The vulnerability affects core communication components, potentially allowing attackers to execute malicious payloads remotely, leading to data breaches, system compromise, or disruption of communication services. No patches or mitigations have been officially released yet, and no known exploits have been observed in the wild, but the risk remains significant given the nature of the flaw and the criticality of the affected components.

The impact of CVE-2025-66956 is severe for organizations using Asseco SEE Live 2.0, particularly those relying on its communication modules for business-critical operations. Successful exploitation can lead to unauthorized execution of attachments, resulting in potential data exfiltration, malware deployment, or disruption of communication channels such as email, SMS, and fax services. This can compromise confidentiality by exposing sensitive information, integrity by allowing unauthorized changes or execution of malicious code, and availability by disrupting essential communication workflows. Organizations may face operational downtime, reputational damage, regulatory penalties, and financial losses. The requirement for low privileges to exploit the vulnerability increases the risk from insider threats or attackers who have gained limited access. The lack of user interaction needed further broadens the attack surface. Given the critical CVSS score and the scope of affected components, the vulnerability poses a high risk to enterprises, government agencies, and service providers using this software.

Since no official patches are currently available, organizations should implement immediate compensating controls. These include restricting network access to the affected Asseco SEE Live 2.0 components by using firewalls and network segmentation to limit exposure to trusted users and systems only. Enforce strict privilege management and monitor for unusual access patterns or attempts to access attachments via URLs. Employ application-layer gateways or proxies that can inspect and block suspicious URL requests or attachment executions. Conduct thorough audits of user privileges and revoke unnecessary access rights to reduce the risk of privilege escalation. Implement endpoint protection solutions capable of detecting and blocking malicious payloads executed from attachments. Additionally, organizations should prepare incident response plans tailored to this vulnerability and monitor vendor communications for forthcoming patches or updates. Regularly update and patch other system components to reduce the overall attack surface and consider isolating critical communication services until a fix is available.