CVE-2023-36038 is a high-severity vulnerability classified under CWE-400, indicating uncontrolled resource consumption in Microsoft ASP.NET Core 8.0. This vulnerability allows an unauthenticated remote attacker to trigger a denial of service (DoS) condition by exploiting the way ASP.NET Core 8.0 handles resource allocation and consumption. Specifically, the flaw arises from the application's inability to properly limit or manage resource usage under certain conditions, which can lead to excessive consumption of CPU, memory, or other system resources. The vulnerability has a CVSS 3.1 base score of 8.2, reflecting its high impact on availability with no required privileges or user interaction, and can be exploited remotely over the network. The attack vector is network-based (AV:N), with low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component itself. While confidentiality is not affected, integrity impact is low, and availability impact is high, indicating the primary risk is service disruption. No known exploits are reported in the wild yet, and no official patches have been linked at the time of publication. This vulnerability affects only version 8.0 of ASP.NET Core, a widely used web application framework for building modern web services and APIs on the Microsoft .NET platform. Given the critical role of ASP.NET Core in enterprise and cloud environments, exploitation could significantly disrupt web services, leading to downtime and potential cascading effects on dependent systems.

For European organizations, the impact of CVE-2023-36038 could be substantial, especially for those relying on ASP.NET Core 8.0 for critical web applications and APIs. The vulnerability enables denial of service attacks that can degrade or completely disrupt service availability, impacting business continuity, customer trust, and operational efficiency. Sectors such as finance, healthcare, government, and e-commerce—where ASP.NET Core is commonly deployed—are particularly vulnerable to service outages that could result in financial losses, regulatory non-compliance, and reputational damage. Additionally, cloud service providers and managed service providers hosting ASP.NET Core 8.0 applications may face widespread service interruptions affecting multiple clients. The lack of required authentication or user interaction lowers the barrier for attackers, increasing the likelihood of opportunistic attacks. Although no exploits are currently known in the wild, the high CVSS score and ease of exploitation suggest that threat actors may develop exploits soon, making proactive mitigation critical. The impact is primarily on availability, but prolonged outages could indirectly affect data integrity and confidentiality due to emergency recovery actions or fallback procedures.

1. Immediate mitigation involves upgrading or patching ASP.NET Core 8.0 to a fixed version once Microsoft releases an official update. Monitoring Microsoft’s security advisories and applying patches promptly is essential. 2. Until patches are available, implement resource limiting controls at the infrastructure level, such as configuring rate limiting, connection throttling, and request size limits on web servers and reverse proxies (e.g., IIS, NGINX, or Azure Application Gateway) to reduce the risk of resource exhaustion. 3. Deploy Web Application Firewalls (WAFs) with custom rules to detect and block anomalous traffic patterns indicative of DoS attempts targeting ASP.NET Core endpoints. 4. Use robust monitoring and alerting systems to detect unusual spikes in CPU, memory, or network usage that could signal exploitation attempts. 5. Employ network-level protections such as IP reputation filtering and geo-blocking to limit exposure to untrusted sources, especially from regions with no legitimate business interactions. 6. Conduct thorough code reviews and testing of custom ASP.NET Core applications to identify and mitigate any additional resource consumption issues. 7. Consider architectural adjustments such as deploying applications behind load balancers with health checks and automatic failover to maintain availability during attack attempts. 8. Educate development and operations teams about this vulnerability to ensure rapid response and incident handling.