What is CVE-2026-120818?

CVE-2026-120818 is a high-severity vulnerability in MongoDB Server, classified under Use After Free. CVSS score: 7.1/10. Published 2026-11-10.

How severe is CVE-2026-120818?

High severity. CVSS v3 base score is 7.1 out of 10.

Use After Free in MongoDB Server

CVE-2026-120818

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 class: Use-After-Free

Published 2026-11-10 · last modified 2026-11-10.

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

MongoDB Server

Weakness classification (CWE)

CWE-416 — Use After Free

References

jira.mongodb.org/browse/SERVER-135727

Frequently asked questions

What is CVE-2026-120818?: CVE-2026-120818 is a high-severity vulnerability in MongoDB Server, classified under Use After Free. CVSS score: 7.1/10. Published 2026-11-10.
How severe is CVE-2026-120818?: High severity. CVSS v3 base score is 7.1 out of 10.