CVE-2025-30949 is a critical security vulnerability classified under CWE-502, which pertains to the deserialization of untrusted data. This vulnerability affects the 'Site Chat on Telegram' product developed by Guru Team, specifically versions up to 1.0.4. Deserialization vulnerabilities occur when an application deserializes data from untrusted sources without sufficient validation or sanitization, allowing attackers to inject malicious objects. In this case, the vulnerability enables object injection, which can lead to remote code execution, privilege escalation, or other severe impacts on the confidentiality, integrity, and availability of the affected system. The CVSS v3.1 base score of 9.8 reflects the critical nature of this flaw, indicating that it can be exploited remotely over the network without any authentication or user interaction. The vulnerability allows an attacker to send crafted serialized data to the Site Chat on Telegram service, which then processes this data insecurely, leading to potentially arbitrary code execution or system compromise. Although no public exploits are currently known in the wild, the high severity score and the nature of the vulnerability suggest that exploitation could be straightforward for skilled attackers once a proof of concept is developed. The lack of available patches at the time of publication increases the urgency for affected users to implement mitigations and monitor for updates from the vendor.

For European organizations, the impact of this vulnerability could be substantial, especially for those relying on the Guru Team's Site Chat on Telegram for internal or customer communications. Successful exploitation could lead to unauthorized access to sensitive communications, data leakage, disruption of chat services, and potential lateral movement within corporate networks. This could compromise personal data protected under GDPR, leading to regulatory penalties and reputational damage. Additionally, the ability to execute arbitrary code remotely without authentication increases the risk of widespread compromise, ransomware deployment, or espionage activities. Organizations in sectors such as finance, healthcare, government, and critical infrastructure, which often use secure communication tools, could face heightened risks. The disruption of communication channels could also affect operational continuity and incident response capabilities.

Given the absence of official patches, European organizations should take immediate and specific mitigation steps beyond generic advice: 1) Restrict network access to the Site Chat on Telegram service using firewall rules or network segmentation to limit exposure to trusted internal users only. 2) Implement strict input validation and monitoring on any interfaces interacting with serialized data, if customization or middleware is possible. 3) Employ runtime application self-protection (RASP) or web application firewalls (WAF) with custom rules to detect and block suspicious serialized payloads or anomalous traffic patterns targeting the chat service. 4) Monitor logs and network traffic for unusual deserialization activity or error messages indicative of exploitation attempts. 5) Prepare incident response plans specifically addressing potential exploitation of deserialization vulnerabilities, including isolating affected systems and forensic analysis. 6) Engage with the vendor for timely updates and patches, and plan for rapid deployment once available. 7) Consider alternative secure communication tools temporarily if risk exposure is high and mitigation controls are insufficient.