MongoDB Server Use-After-Free in Aggregation Framework (CVE-2026-120821)
CVE-2026-120821 Published on November 10, 2026
Post-authentication use-after-free in MongoDB Server aggregation sub-pipelines
A use-after-free in the aggregation framework of MongoDB Server can occur when certain expressions are evaluated in an aggregation sub-pipeline. The condition can be caused by an authenticated user with read privileges, and may result in the server terminating unexpectedly.
Vulnerability Analysis
CVE-2026-120821 can be exploited 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-2026-120821 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-120821
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Affected Versions
MongoDB Server:- Version 9.0.0 and below 9.0.7 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.