MongoDB Server JS Exec Memory Release UAF Info Leak
CVE-2026-120819 Published on November 10, 2026
Use-after-free in Wasm JS-BSON bridge lets read-only users read 24 KiB via $accumulator
A memory-management flaw in the server-side JavaScript execution component of MongoDB Server can allow an authenticated user holding only read privileges to cause the server to access memory that has already been released. By submitting a specially crafted database command that runs user-supplied JavaScript, the user can cause a bounded amount of adjacent process memory to be returned in the command's result. This results in the user obtaining information they are not authorized to access. Integrity and availability are not affected.
Vulnerability Analysis
CVE-2026-120819 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-2026-120819 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-120819
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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.