CVE-2025-27531 is a critical security vulnerability classified under CWE-502, which pertains to the deserialization of untrusted data. This vulnerability affects Apache InLong versions from 1.13.0 up to but not including 2.1.0. Apache InLong is an open-source data integration framework developed by the Apache Software Foundation, widely used for collecting, aggregating, and transmitting large volumes of data in distributed environments. The vulnerability arises due to improper handling of serialized data inputs, allowing an authenticated attacker to exploit the deserialization process. Specifically, the attacker can perform a double write of a parameter, which leads to the ability to read arbitrary files on the affected system. This can result in unauthorized disclosure of sensitive information, potentially including configuration files, credentials, or other critical data stored on the server. The CVSS v3.1 base score of 9.8 indicates a critical severity level, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The impact affects confidentiality, integrity, and availability (C:H/I:H/A:H), meaning the vulnerability could be exploited remotely without authentication or user interaction, leading to full compromise of the system. The issue has been addressed in Apache InLong version 2.1.0, and users are strongly advised to upgrade to this version to mitigate the risk. No known exploits are currently reported in the wild, but the critical nature and ease of exploitation make it a high-risk vulnerability that should be prioritized for remediation.

For European organizations, the impact of CVE-2025-27531 can be substantial, especially for those relying on Apache InLong for data integration and processing tasks. Exploitation could lead to unauthorized access to sensitive corporate data, including personal data protected under GDPR, intellectual property, or operational data critical to business continuity. The ability to read arbitrary files could also facilitate further attacks, such as credential theft, lateral movement within networks, or disruption of services. Given the critical severity and the fact that no authentication or user interaction is required, attackers could potentially compromise systems remotely and at scale. This poses a significant risk to sectors that handle large volumes of data, such as finance, telecommunications, healthcare, and government agencies across Europe. The breach of confidentiality and integrity could result in regulatory penalties, reputational damage, and financial losses. Additionally, the availability impact could disrupt data pipelines, affecting business operations and service delivery.

To mitigate this vulnerability effectively, European organizations should: 1) Immediately upgrade Apache InLong to version 2.1.0 or later, as this version contains the official patch addressing the deserialization flaw. 2) Implement strict input validation and sanitization on all serialized data inputs to prevent malicious payloads from being processed. 3) Restrict network access to Apache InLong management interfaces and APIs to trusted internal networks or VPNs, minimizing exposure to external threats. 4) Employ application-layer firewalls or intrusion detection/prevention systems (IDS/IPS) to monitor and block suspicious deserialization attempts or anomalous parameter manipulations. 5) Conduct thorough audits and monitoring of logs related to Apache InLong to detect any unusual file access patterns or parameter anomalies. 6) Establish a rapid incident response plan to isolate and remediate affected systems if exploitation is suspected. 7) Educate development and operations teams about secure deserialization practices and the risks associated with untrusted data processing.