CVE-2026-8336: After invoking $_internalJsEmit, which is not intended to be directly accessible, or mapreduce command’s map f

Routine

HIGH 7.5UPGRADE

CVE-2026-8336 is a high-severity flaw (CVSS 7.5) affecting mongodb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 versio

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 83%)
CISA exploited list	No
Weakness	CWE-416
Published	2026-05-13
Last modified	2026-10-26

Publisher (CNA): MongoDB, Inc. · Vendor: mongodb

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-13 04:17 UTCPublished CVE record published
2026-10-26 18:10 UTCUpdated Record last modified

mongodb mongodb UPGRADE

Affected: >= 8.2.0 and < 8.2.9 · >= 8.3.0 and < 8.3.2

Fixed in: 8.2.9, 8.3.2

Safe to downgrade to: a release before 8.2.0

1. Check installed version

apt-cache policy mongodb || rpm -q mongodb || mongodb --version

2. UPGRADE to 8.2.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mongodb

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mongodb

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 8.2.0 (Debian / Ubuntu)

apt-cache madison mongodb sudo apt install mongodb=<VERSION_BEFORE_8.2.0> sudo apt-mark hold mongodb

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mongodb sudo dnf downgrade mongodb-<VERSION_BEFORE_8.2.0> sudo dnf versionlock add mongodb

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-8336?

mongodb: upgrade to 8.2.9, 8.3.2. Exact commands for each OS are on this page.

Is CVE-2026-8336 being exploited?

CVE-2026-8336 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-8336 affect?

CVE-2026-8336 affects mongodb. Severity is high (CVSS 7.5). 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 $whe

How urgent is CVE-2026-8336?

Priority 30/100. High severity

Software pages

MongoDB vulnerabilities

Related CVEs

CVE-2026-8063 MEDIUM 6.5 UPGRADE An authenticated user can crash mongod when running $rankFusion or $scoreFusion with an empty pipeline on a vi
CVE-2026-6914 MEDIUM 6.5 UPGRADE Computing the MD5 checksum of a malformed BSON object under specific conditions may cause loss of availability
CVE-2026-6915 MEDIUM 6.3 UPGRADE An authorization flaw in the user management command could allow an authenticated user to make limited changes
CVE-2026-8053 HIGH 8.8 UPGRADE An issue in MongoDB Server's time-series collection implementation allows an authenticated user with database
CVE-2026-8199 MEDIUM 6.5 UPGRADE An authenticated user can cause excess memory usage via bitwise match expression AST processing of $bitsAllSet

References

← Back to latest CVEs