MongoDB C Driver Namespace Field Bypass: Crash & Memory Disclosure
CVE-2026-120956 Published on November 3, 2026
remote abort and memory disclosure from a malformed cursor.ns
The MongoDB C Driver does not validate the type or format of a namespace field returned by the server in a query response. A MongoDB endpoint that a client application connects to, without needing any credentials, can return a malformed value in that field. This causes the client application process to terminate, and can also cause the driver to read memory outside an allocated buffer and to send a small amount of the application's own uninitialized heap memory back to the endpoint in a follow-up command. The impact is limited to the process that embeds the driver.
Vulnerability Analysis
CVE-2026-120956 is exploitable with network access. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is an assertion failure Vulnerability?
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
CVE-2026-120956 has been classified to as an assertion failure vulnerability or weakness.
Products Associated with CVE-2026-120956
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Affected Versions
MongoDB C Driver:- Version 1.25.0, <= 1.30.14 is affected.
- Version 2.0.0, <= 2.5.7 is affected.