CVE-2026-120819: Use-After-Free (CVSS 4.3)

Description

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.

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0038

Probability of exploitation

0.33%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-416 Use After Free

References

Other References

https://jira.mongodb.org/browse/SERVER-134893

Frequently Asked Questions

What is CVE-2026-120819? +

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. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-120819? +

CVE-2026-120819 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0038, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-120819? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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