CVE-2026-25613 is a vulnerability identified in MongoDB Server versions 7.0, 8.0, and 8.2, caused by incorrect type conversion or casting (CWE-704) when processing compound wildcard indexes. Specifically, an authorized user can issue a query against a collection containing an invalid compound wildcard index, which triggers improper handling within the server code. This results in the ability to disable the MongoDB server, effectively causing a denial-of-service (DoS) condition. The vulnerability does not require user interaction and has a low attack complexity, but it does require the attacker to have at least limited privileges (authorized user) on the database server. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and a high impact on availability (VA:H), with no impact on confidentiality or integrity. No known exploits are currently reported in the wild, but the potential for disruption is significant given MongoDB’s widespread use in enterprise environments. The root cause lies in the server’s failure to correctly validate or cast types when handling compound wildcard indexes, which are advanced indexing structures used to optimize queries involving multiple fields. Improper handling of these indexes can lead to server crashes or forced shutdowns. This vulnerability highlights the importance of robust input validation and type safety in database management systems, especially for complex features like compound wildcard indexes. MongoDB administrators should be aware of this issue and monitor for suspicious queries or attempts to create invalid indexes. Since no patches are currently linked, organizations should apply compensating controls to limit exposure until official fixes are released.

The primary impact of CVE-2026-25613 is denial of service, where an authorized user can disable the MongoDB server by exploiting the vulnerability. For European organizations, this can lead to significant operational disruptions, especially for those relying on MongoDB for critical applications such as financial services, healthcare, government databases, and e-commerce platforms. Availability loss can result in downtime, loss of customer trust, regulatory compliance issues (e.g., GDPR mandates on service availability), and financial losses. Since the vulnerability requires authorized user access, insider threats or compromised credentials could be leveraged to exploit this flaw. The lack of impact on confidentiality or integrity reduces risks related to data breaches or tampering, but the availability impact alone is critical for service continuity. Organizations with large-scale MongoDB deployments or those using compound wildcard indexes extensively are at higher risk. Additionally, the vulnerability could be used as part of a multi-stage attack to cause disruption while other malicious activities are conducted. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits post-disclosure.

1. Restrict index creation privileges strictly to trusted database administrators to prevent unauthorized users from creating or manipulating compound wildcard indexes. 2. Monitor database logs and query patterns for attempts to create or query invalid compound wildcard indexes, setting up alerts for suspicious activity. 3. Implement network segmentation and access controls to limit which users can connect to MongoDB servers, reducing the risk of exploitation by unauthorized or compromised accounts. 4. Apply principle of least privilege to all MongoDB users, ensuring that only necessary permissions are granted, minimizing the attack surface. 5. Until an official patch is released, consider disabling or avoiding the use of compound wildcard indexes if feasible, or validate index definitions rigorously before deployment. 6. Keep MongoDB server versions up to date and subscribe to MongoDB security advisories to apply patches promptly once available. 7. Conduct regular security audits and penetration testing focusing on database configurations and privilege management to detect potential exploitation paths. 8. Employ runtime protection tools or database activity monitoring solutions that can detect and block anomalous queries targeting index structures.