CVE-2026-1848 is a vulnerability identified in MongoDB Server versions 7.0, 8.0, and 8.2, related to improper resource allocation and lack of throttling on connections accepted via the proxy port. Specifically, connections received through the proxy port do not increment the total accepted connections count, which is intended to limit resource consumption. This oversight allows an attacker to open an excessive number of connections through the proxy port, bypassing connection limits and exhausting server resources such as memory and file descriptors. The result is a denial-of-service (DoS) condition where the MongoDB server crashes or becomes unresponsive due to resource exhaustion. The vulnerability is categorized under CWE-770, which involves allocation of resources without proper limits or throttling. The CVSS 4.0 score of 8.2 reflects a high severity, with an attack vector over the network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on availability (VA:H). The vulnerability does not affect confidentiality or integrity but severely impacts availability. No known exploits have been reported in the wild yet, but the potential for DoS attacks is significant. The vulnerability affects MongoDB servers that expose the proxy port, which is often used in load balancing or proxying scenarios. Since the proxy protocol header is pending when connections are accepted, the server fails to properly account for these connections in its resource management. This flaw can be exploited remotely without authentication, making it a critical concern for exposed MongoDB deployments. The lack of patch links suggests that a fix may still be pending or in development, emphasizing the need for immediate mitigation strategies.

For European organizations, the impact of CVE-2026-1848 is primarily a denial-of-service condition that can disrupt critical database services. MongoDB is widely used across various sectors including finance, healthcare, telecommunications, and government services in Europe. A successful exploitation could lead to downtime, loss of availability of essential applications, and potential cascading effects on dependent systems. Organizations relying on MongoDB for real-time data processing or customer-facing applications could experience significant operational disruptions. The inability to properly limit proxy port connections can be exploited by attackers to overwhelm servers, potentially causing outages during peak business hours or critical operations. This may also affect cloud service providers hosting MongoDB instances, impacting multiple tenants and services. The disruption could lead to financial losses, reputational damage, and regulatory scrutiny, especially under GDPR where service availability is a component of data protection obligations. Given the remote, unauthenticated nature of the exploit, attackers can launch attacks from anywhere, increasing the risk for organizations with exposed MongoDB proxy ports.

1. Immediately restrict access to the MongoDB proxy port by implementing network-level controls such as firewalls or access control lists (ACLs) to allow only trusted IP addresses. 2. Deploy rate limiting and connection throttling mechanisms on perimeter devices or proxies to limit the number of concurrent connections from any single source. 3. Monitor MongoDB server metrics closely, focusing on connection counts, resource utilization, and unusual spikes in proxy port connections. 4. If possible, disable the proxy port if it is not required for your deployment or replace it with more secure alternatives. 5. Stay updated with MongoDB vendor advisories and apply patches promptly once available. 6. Consider deploying Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) that can detect and block abnormal connection patterns targeting the proxy port. 7. Conduct regular security assessments and penetration testing to identify exposure of proxy ports and validate mitigation effectiveness. 8. Implement robust logging and alerting for connection anomalies to enable rapid incident response. 9. For cloud deployments, leverage cloud provider security groups and network policies to restrict proxy port exposure. 10. Educate DevOps and security teams about this vulnerability to ensure proactive management and monitoring.