MongoDB Server Use-After-Free in ServerSide JS Aggregation
CVE-2026-120818 Published on November 10, 2026
Use-After-Free in MongoDB Server JavaScript Support for Aggregation Leads to Information Disclosure
A use-after-free weakness in MongoDB Server's server-side JavaScript support for aggregation may allow a stale reference to previously freed process memory to be read and returned. An authenticated user with minimal or no assigned roles can trigger this condition over the normal network protocol by submitting a single crafted aggregation request, with no additional privileges or non-default configuration. Successful triggering this issue may result in adjacent process memory contents being returned, including data that undermines memory-layout randomization, and may in some cases affect server availability.
Vulnerability Analysis
CVE-2026-120818 is exploitable with network access, and requires small amount of user privileges. 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 a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-120818 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-120818
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Affected Versions
MongoDB Server:- Version 8.3.0 and below 8.3.16 is affected.
- Version 8.0.0 and below 8.0.37 is affected.
- Version 7.0.0 and below 7.0.48 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.