CVE-2023-5997 is a use-after-free vulnerability identified in the garbage collection subsystem of Google Chrome prior to version 119.0.6045.159. Use-after-free vulnerabilities occur when a program continues to use memory after it has been freed, leading to undefined behavior such as heap corruption. In this case, the garbage collector incorrectly manages memory, allowing a remote attacker to craft a malicious HTML page that triggers this flaw. When a user visits such a page, the heap corruption can be exploited to execute arbitrary code within the context of the browser process. This type of vulnerability is critical because it can bypass security boundaries and potentially allow attackers to take control of the affected system. The vulnerability requires no authentication but does require user interaction (visiting a malicious webpage). Although no active exploits have been reported, the widespread use of Chrome makes this a high-risk issue. The vulnerability was publicly disclosed on November 15, 2023, with a patch released in Chrome version 119.0.6045.159. The absence of a CVSS score necessitates a severity assessment based on the nature of the flaw, its impact, and exploitation conditions.

For European organizations, this vulnerability poses a significant risk due to the extensive use of Google Chrome across enterprises, government agencies, and critical infrastructure sectors. Successful exploitation could lead to arbitrary code execution, enabling attackers to compromise confidentiality, integrity, and availability of systems. This could result in data breaches, unauthorized access to sensitive information, disruption of services, and potential lateral movement within networks. Given the browser's role as a primary interface to the internet, the attack surface is broad, affecting employees, contractors, and partners. Industries such as finance, healthcare, energy, and public administration are particularly vulnerable due to the sensitivity of their data and the critical nature of their operations. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits rapidly following public disclosure. The vulnerability's remote exploitation vector and ease of triggering through web content increase the urgency for mitigation.

European organizations should immediately update all instances of Google Chrome to version 119.0.6045.159 or later to remediate the vulnerability. Beyond patching, organizations should implement web content filtering and employ browser security features such as sandboxing and site isolation to limit the impact of potential exploitation. Deploy endpoint detection and response (EDR) solutions capable of identifying anomalous browser behavior indicative of exploitation attempts. Conduct user awareness training emphasizing the risks of visiting untrusted websites and the importance of timely software updates. Network-level protections, including intrusion prevention systems (IPS) with signatures for suspicious heap corruption patterns, can provide additional defense layers. For high-risk environments, consider restricting browser usage to trusted sites or using browser isolation technologies to contain potential threats. Maintain an inventory of browser versions in use across the organization to ensure compliance with update policies. Regularly monitor threat intelligence feeds for any emerging exploits related to this vulnerability.