How severe is CVE-2026-9747?

No CVSS score has been assigned to CVE-2026-9747 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-9747?

Affected package information for CVE-2026-9747 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-9747?

Upgrade the affected component to the fixed release for CVE-2026-9747, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.

How do I detect CVE-2026-9747 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2026-9747 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-9747 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-9747 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-9747?

CVE-2026-9747 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 38th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-9747?

CVE-2026-9747 is classified as Reachable Assertion (CWE-617). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-9747 published, and has it been updated?

CVE-2026-9747 was published on June 9, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Not in CISA KEV

CVE-2026-9747 — mongo

CVE-2026-9747 is a Reachable Assertion vulnerability. A fix is available — see the affected versions and patch details below.

Crafted cross-shard merge aggregation crashes MongoDB Server

Also known asBIT-mongodb-2026-9747

Published

Jun 9, 2026

Updated

Aug 12, 2026

Affected

1 product

Patched

See advisory

Exploits

None indexed

Exploitation data as of Sep 30, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-9747.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs38th percentile — riskier than 38% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Description

Adding fromRouter:true and runtimeConstants.userRoles could cause aggregations to crash mongodb server.

Affected Products

1 product · 4 configurations

Application

mongodbmongodb

≥ 8.3.0 && < 8.3.3

range

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for CVE-2026-9747, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

Adding fromRouter:true and runtimeConstants.userRoles could cause aggregations to crash mongodb server.

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