CVE-2026-18706: An issue in MongoDB Server's $graphLookup aggregation stage could allow an authenticated user able to issue ag

Routine

MEDIUM 6.6UPGRADEDOWNGRADE

CVE-2026-18706 is a medium-severity flaw (CVSS 6.6) affecting mongodb, mongodb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue in MongoDB Server's $graphLookup aggregation stage could allow an authenticated user able to issue aggregation and memory-management commands to cause an internal reference to be used after the underlying memory has been freed. This could result in a server crash or, potentially, execution of unintended code.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.6 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	High
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-416
Published	2026-08-11
Last modified	2026-10-23

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

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-11 19:17 UTCPublished CVE record published
2026-10-23 21:10 UTCUpdated Record last modified

mongodb mongodb UPGRADE

Affected: >= 8.3.0 and < 8.3.8

Fixed in: 8.3.8

Safe to downgrade to: a release before 8.3.0

1. Check installed version

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

2. UPGRADE to 8.3.8 (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 8.3.0 (Debian / Ubuntu)

apt-cache madison mongodb sudo apt install mongodb=<VERSION_BEFORE_8.3.0> 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_8.3.0> 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.

mongodb mongodb DOWNGRADE

Affected: 9.0.0 alpha0 · 9.0.0 alpha1

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 9.0.0 (Debian / Ubuntu)

apt-cache madison mongodb sudo apt install mongodb=<VERSION_BEFORE_9.0.0> sudo apt-mark hold mongodb

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mongodb sudo dnf downgrade mongodb-<VERSION_BEFORE_9.0.0> 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-2026-18706?

mongodb: upgrade to 8.3.8; mongodb: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-18706 being exploited?

CVE-2026-18706 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-2026-18706 affect?

CVE-2026-18706 affects mongodb, mongodb. Severity is medium (CVSS 6.6). An issue in MongoDB Server's $graphLookup aggregation stage could allow an authenticated user able to issue aggregation and memory-management commands to cause an internal reference to be used after the underlying memory has been freed. Thi

How urgent is CVE-2026-18706?

Priority 33/100. No elevated risk signals yet.

Software pages

MongoDB vulnerabilities

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References

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