CVE-2026-25611 is a vulnerability identified in MongoDB Server versions 7.0, 8.0, and 8.2, categorized under CWE-405 (Asymmetric Resource Consumption). The flaw arises from the server's handling of certain unauthenticated, specially crafted messages that cause disproportionate resource usage, specifically memory exhaustion. An attacker can exploit this by sending these crafted messages remotely without any authentication or user interaction, leading to the MongoDB server consuming excessive memory resources until it crashes or becomes unresponsive. This results in a denial-of-service (DoS) condition impacting the availability of the database service. The vulnerability has a CVSS 4.0 base score of 8.7, indicating high severity, with attack vector being network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and a high impact on availability (VA:H). No known exploits have been reported in the wild yet, but the ease of exploitation and potential impact make it a critical concern for organizations using affected MongoDB versions. The lack of authentication requirements means that any attacker with network access to the MongoDB server can attempt exploitation. The vulnerability highlights the importance of securing MongoDB instances, especially those exposed to untrusted networks. Currently, no official patches are linked, suggesting that organizations should monitor MongoDB advisories closely for updates. In the interim, network-level protections and monitoring are essential to mitigate risk.

For European organizations, the impact of CVE-2026-25611 is primarily on the availability of MongoDB services. Many enterprises, public sector entities, and critical infrastructure providers in Europe rely on MongoDB for data storage and application backends. A successful exploitation could lead to service outages, disrupting business operations, customer-facing applications, and internal workflows. This could result in financial losses, reputational damage, and potential regulatory scrutiny, especially under GDPR where service availability is a component of data protection obligations. Organizations in sectors such as finance, healthcare, telecommunications, and government are particularly vulnerable due to their reliance on continuous database availability. Additionally, the unauthenticated nature of the attack vector increases the risk from external threat actors, including cybercriminals and hacktivists. The lack of known exploits in the wild currently reduces immediate risk, but the vulnerability’s characteristics suggest it could be weaponized quickly once exploit code becomes available. The potential for denial-of-service conditions also raises concerns for cloud-hosted MongoDB instances and managed services used by European companies, which may propagate impact across multiple tenants or services.

1. Apply official patches from MongoDB Inc immediately upon release to remediate the vulnerability. 2. Until patches are available, restrict network access to MongoDB servers using firewalls, VPNs, or network segmentation to limit exposure to trusted hosts only. 3. Disable or restrict remote access to MongoDB instances, especially those exposed to the internet. 4. Implement network intrusion detection and prevention systems (IDS/IPS) to monitor for anomalous or suspicious traffic patterns that could indicate exploitation attempts involving crafted messages. 5. Employ rate limiting and connection throttling on MongoDB endpoints to reduce the risk of resource exhaustion attacks. 6. Regularly audit MongoDB server configurations to ensure authentication and authorization mechanisms are properly enforced, even though this vulnerability does not require authentication. 7. Monitor server resource usage closely to detect early signs of memory exhaustion or abnormal behavior. 8. Consider deploying MongoDB instances behind application-layer proxies or gateways that can filter and validate incoming traffic. 9. Educate IT and security teams about this vulnerability and ensure incident response plans include steps for handling potential DoS attacks on database infrastructure.