CVE-2025-5222 is a high-severity stack-based buffer overflow vulnerability identified in the International Components for Unicode (ICU) library, specifically affecting the 'genrb' binary used within Red Hat Enterprise Linux 10. The vulnerability arises from improper handling of the 'subtag' struct within the SRBRoot::addTag function, where a buffer copy operation occurs without verifying the size of the input data. This classic buffer overflow flaw can lead to memory corruption, which attackers may exploit to execute arbitrary code locally on the affected system. The vulnerability requires local access with high attack complexity and user interaction, but no privileges are needed to trigger it. The CVSS v3.1 base score is 7.0, reflecting high impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the nature of the vulnerability and its presence in a widely used Unicode processing library make it a significant risk. The ICU library is a critical component for handling Unicode data and is commonly integrated into various applications and system utilities, meaning that exploitation could compromise system stability and security. Since the vulnerability is local and requires user interaction, it may be leveraged by malicious insiders or through social engineering to escalate privileges or execute arbitrary code on Red Hat Enterprise Linux 10 systems.

For European organizations, the impact of CVE-2025-5222 could be substantial, especially for those relying on Red Hat Enterprise Linux 10 in production environments. The vulnerability could allow attackers with local access to execute arbitrary code, potentially leading to unauthorized data access, system compromise, or disruption of critical services. This is particularly concerning for sectors with stringent data protection requirements such as finance, healthcare, and government institutions across Europe. Exploitation could result in breaches of sensitive personal or corporate data, violating GDPR and other regulatory frameworks. Additionally, the memory corruption caused by the buffer overflow could destabilize systems, leading to denial of service conditions. Given that the vulnerability requires user interaction, phishing or social engineering campaigns could be used to trick users into triggering the flaw, increasing the attack surface. The absence of known exploits in the wild currently reduces immediate risk, but the high severity and potential for local privilege escalation necessitate proactive mitigation to protect European infrastructure and data.

To mitigate CVE-2025-5222 effectively, European organizations should: 1) Apply security patches from Red Hat as soon as they become available, as no patch links are currently provided but are expected given the vulnerability's publication. 2) Restrict local access to systems running Red Hat Enterprise Linux 10, enforcing strict user authentication and minimizing the number of users with local login capabilities. 3) Implement application whitelisting and endpoint protection solutions to detect and prevent exploitation attempts involving the 'genrb' binary or related ICU components. 4) Conduct user awareness training focused on recognizing social engineering and phishing attempts that could lead to user interaction triggering the vulnerability. 5) Monitor system logs and behavior for anomalies indicative of exploitation attempts, such as unexpected crashes or unusual execution of the genrb binary. 6) Consider deploying runtime application self-protection (RASP) or memory protection technologies that can detect and block buffer overflow attacks in real time. 7) For critical systems, employ sandboxing or containerization to limit the impact of potential exploitation. These targeted measures go beyond generic advice by focusing on controlling local access, user behavior, and monitoring specific vulnerable components.