MongoDB Server Use-After-Free in Plan Cache (CVE2026120811)
CVE-2026-120811 Published on November 10, 2026
Use-After-Free in MongoDB Server Classic Query Engine Plan Cache Leads to Information Disclosure and Denial of Service
A use-after-free issue exists in the MongoDB servers classic query engine plan cache. Under certain query conditions, an unowned reference to data from an earlier command can be retained in cached plan statistics. After the originating memory is freed, a subsequent diagnostic command serializing those statistics can read freed heap memory, potentially returning sensitive server process memory contents to the authenticated client. Under certain heap reuse conditions, this may also cause the server to crash.
Vulnerability Analysis
CVE-2026-120811 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-2026-120811 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-120811
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Affected Versions
MongoDB Server:- Version 9.0.0 and below 9.0.7 is affected.
- 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.