CVE-2025-6706 is a use-after-free vulnerability (CWE-416) identified in MongoDB Server versions 6.0 prior to 6.0.21, 7.0 prior to 7.0.17, and 8.0 prior to 8.0.4 when the Slot-Based Execution (SBE) engine is enabled. This vulnerability can be triggered by an authenticated user through a carefully crafted aggregation framework operation that uses a specific combination of rarely-used aggregation pipeline expressions. The use-after-free condition can lead to a server crash and other unexpected behaviors. Notably, the attacker does not require authorization to shut down the server, only authenticated access is necessary. The vulnerability arises from improper memory management within the aggregation pipeline processing, where objects are freed prematurely but still accessed afterward, causing instability. The CVSS v3.1 base score is 5.0 (medium severity), reflecting network attack vector, high attack complexity, low privileges required, no user interaction, and limited impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, and no official patches or mitigation links were provided at the time of publication (June 26, 2025).

For European organizations, this vulnerability poses a risk primarily to those using affected MongoDB Server versions with the SBE engine enabled. Exploitation could result in denial of service (DoS) through server crashes, disrupting critical applications relying on MongoDB databases. This could affect sectors such as finance, healthcare, e-commerce, and public services where MongoDB is used for data storage and analytics. Although the impact on confidentiality and integrity is limited, repeated crashes could lead to data unavailability and potential operational downtime. Given the medium severity and the requirement for authenticated access, the threat is more significant in environments with weak access controls or where internal users or compromised accounts could exploit the flaw. The lack of known exploits reduces immediate risk but does not eliminate the potential for future attacks, especially in targeted scenarios. European organizations with high availability requirements and those operating critical infrastructure should be particularly vigilant.

1. Immediate upgrade to MongoDB Server versions 6.0.21, 7.0.17, or 8.0.4 (or later) once patches are released to address this vulnerability. 2. Restrict and audit authenticated user access to MongoDB instances, enforcing the principle of least privilege to minimize the number of users who can execute aggregation operations. 3. Monitor MongoDB logs for unusual or complex aggregation pipeline queries that could indicate exploitation attempts. 4. Disable or restrict the use of the SBE engine if feasible, or apply configuration hardening to limit exposure until patches are applied. 5. Implement network segmentation and firewall rules to limit access to MongoDB servers only to trusted hosts and users. 6. Regularly review and update authentication mechanisms, including enforcing strong credentials and multi-factor authentication for database access. 7. Prepare incident response plans to quickly identify and mitigate potential DoS events caused by this vulnerability.