Vulnerability · Published May 13, 2026 · Assigned by mongodb

CVE-2026-8336Post-authentication use-after-free error in $_internalJsEmit and mapreduce commands

High 7.5

In plain English

A high-severity use-after-free in MongoDB Server from MongoDB, Inc.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.3%top 82.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map function in a certain way, an authenticated user can subsequently crash mongod when the server-side JavaScript engine (through $where, $function, mapreduce reduce stage, etc.) is used also in a specific way, resulting in a post-authentication denial-of-service. This issue impacts MongoDB Server v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Affected products (as reported)

Vendor	Product	Versions
MongoDB, Inc.	MongoDB Server	8.2 – before 8.2.98.3 – before 8.3.2

Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

References

https://jira.mongodb.org/browse/SERVER-121610 issue-tracking