CVE-2026-18712 in Server
Summary
by MITRE • 08/11/2026
An issue in MongoDB Server's Queryable Encryption maintenance operations could allow an authenticated user with privileges on one encrypted collection to cause unauthorized modification or destruction of data belonging to a different collection. This is due to insufficient validation of certain internal metadata references before they are used to perform operations on other namespaces.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability exists within MongoDB Server's implementation of Queryable Encryption features, specifically in how the system handles internal metadata references during maintenance operations. The flaw represents a critical privilege escalation issue that undermines the fundamental security boundaries between encrypted collections. An authenticated user who possesses sufficient privileges on one encrypted collection can exploit this weakness to manipulate or destroy data in unrelated collections through improper validation of metadata references.
The technical root cause stems from inadequate input validation mechanisms within MongoDB's internal encryption maintenance pathways. When performing routine operations such as key rotation, schema updates, or other administrative tasks on encrypted collections, the server fails to properly validate the namespace references contained within internal metadata structures. This allows malicious actors to craft specially crafted operations that redirect these metadata references to target different collections than intended. The vulnerability specifically affects the queryable encryption implementation and operates at the database engine level where internal metadata is processed, making it particularly dangerous as it bypasses normal access control mechanisms.
The operational impact of this vulnerability extends beyond simple data integrity concerns into full data compromise scenarios. An attacker with minimal privileges on one collection could potentially cause catastrophic damage to unrelated encrypted datasets, leading to data loss, corruption, or unauthorized modification of sensitive information. This affects organizations that rely on MongoDB's encryption features for compliance requirements and data protection, as the vulnerability essentially breaks down the isolation guarantees provided by the encryption implementation. The attack vector requires authentication and existing privileges but does not necessitate elevated system access, making it particularly concerning for environments where users may have legitimate access to multiple collections.
Organizations should immediately implement several mitigation strategies to address this vulnerability. The most effective approach involves applying the latest security patches from MongoDB that correct the metadata validation logic in queryable encryption maintenance operations. Additionally, implementing strict privilege controls and least-privilege access models can help minimize the potential impact of exploitation. Network segmentation and monitoring of database maintenance operations should be enhanced to detect anomalous behavior patterns that might indicate attempted exploitation. Security teams should also conduct comprehensive audits of their encrypted collection configurations to identify and remediate any unnecessary cross-collection privileges that could amplify the attack surface.
This vulnerability aligns with common weakness enumerations such as CWE-22, which describes improper limitation of a pathname to a restricted directory, and CWE-863, which covers incorrect authorization. From an adversarial perspective, this issue maps to multiple ATT&CK techniques including privilege escalation through access token manipulation and data destruction via unauthorized modification operations. The vulnerability demonstrates how encryption implementations can introduce new attack vectors when internal metadata handling is not properly secured, highlighting the importance of comprehensive security reviews for cryptographic features in database systems. Organizations should also consider implementing database activity monitoring solutions that can detect unusual patterns in encryption maintenance operations that might indicate exploitation attempts against this specific weakness.