CVE-2025-15222 identifies a deserialization vulnerability in the Dromara Sa-Token library, specifically in the ObjectInputStream.readObject method within the SaSerializerTemplateForJdkUseBase64.java file. This vulnerability arises from unsafe deserialization of Base64-encoded Java objects, which can be manipulated by an attacker to execute arbitrary code or cause denial of service if crafted maliciously. The vulnerability affects all versions of Sa-Token up to and including 1.44.0. Exploitation is remote and does not require user interaction, but it has high complexity, making it difficult to exploit successfully. The attacker needs low privileges, indicating that some level of access to the system or application is necessary. The vendor was notified early but did not provide a patch or response, and no official patch links are available. The CVSS 4.0 vector indicates network attack vector, high attack complexity, no privileges required, no user interaction, and low impact on confidentiality, integrity, and availability. Despite the low CVSS score, the vulnerability is significant because deserialization flaws can lead to severe consequences if exploited. The public disclosure increases the risk of future exploitation, although no known exploits are currently active in the wild.

For European organizations, the impact of this vulnerability depends on the extent of Sa-Token usage within their Java-based authentication or session management systems. Successful exploitation could allow attackers to manipulate session tokens or authentication states, potentially leading to unauthorized access or privilege escalation. However, the high complexity and low CVSS score suggest limited immediate risk. Still, organizations in sectors with high security requirements—such as finance, healthcare, and critical infrastructure—could face reputational damage, data breaches, or service disruptions if exploited. The lack of vendor response and patch availability increases the risk exposure period. Additionally, organizations relying on third-party software that integrates Sa-Token may be indirectly affected. Given the remote attack vector, internet-facing applications using Sa-Token are at higher risk. The vulnerability's low impact rating reflects limited confidentiality, integrity, and availability loss, but the potential for chained attacks or exploitation in complex environments should not be underestimated.

European organizations should immediately audit their environments for Sa-Token usage, especially versions up to 1.44.0. If Sa-Token is in use, consider the following mitigations: 1) Implement strict input validation and sanitization on any serialized data inputs to prevent malicious payloads. 2) Restrict network exposure of services using Sa-Token to trusted internal networks or VPNs to reduce remote attack surface. 3) Employ runtime application self-protection (RASP) or Web Application Firewalls (WAF) with custom rules to detect and block suspicious deserialization patterns. 4) Monitor logs for unusual deserialization activity or errors related to ObjectInputStream.readObject. 5) Where possible, replace Java native serialization with safer alternatives such as JSON or protocol buffers. 6) Engage with the Dromara community or maintainers to track any forthcoming patches or updates. 7) Conduct penetration testing focused on deserialization attacks to identify exploitable vectors. 8) Apply the principle of least privilege to limit the impact of potential exploitation. These steps go beyond generic advice by focusing on network segmentation, monitoring, and alternative serialization methods.