How severe is CVE-2026-9743?

CVE-2026-9743 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-9743 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-9743?

CVE-2026-9743 affects Mongodb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-9743?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-9743 have an EU (EUVD) identifier?

Yes. CVE-2026-9743 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35861.

When was CVE-2026-9743 published?

CVE-2026-9743 was published on 2026-06-09 and last updated on 2026-06-17.

CVE-2026-9743

CVE-2026-9743 is a medium-severity vulnerability in Mongodb with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v4: 7.1
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35861
Weakness: CWE-476
Affected product: Mongodb
Published: 2026-06-09
Last modified: 2026-06-17

Description

In MongoDB Server 8.0, an aggregation stage can leave its _subPipeline field null during processing of certain pipelines. If a getMore is subsequently issued on the same cursor, the server may dereference this null sub-pipeline when reattaching to the operation context, accessing an invalid address and crashing the process. This issue allows an authenticated user who can run aggregation pipelines to cause a denial of service by issuing a specially crafted aggregation followed by getMore on affected versions.

Frequently asked questions

What is CVE-2026-9743?: In MongoDB Server 8.0, an aggregation stage can leave its _subPipeline field null during processing of certain pipelines. If a getMore is subsequently issued on the same cursor, the server may dereference this null sub-pipeline when reattaching to the operation context, accessing an invalid address and crashing the process. This issue allows an authenticated user who can run aggregation pipelines to cause a denial of service by issuing a specially crafted aggregation followed by getMore on affected versions.
How severe is CVE-2026-9743?: CVE-2026-9743 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-9743 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-9743?: CVE-2026-9743 affects Mongodb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-9743?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-9743 have an EU (EUVD) identifier?: Yes. CVE-2026-9743 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35861.
When was CVE-2026-9743 published?: CVE-2026-9743 was published on 2026-06-09 and last updated on 2026-06-17.

References

https://jira.mongodb.org/browse/SERVER-123688

Affected products (1)

cpe:2.3:a:mongodb:mongodb:*:*:*:*:*:*:*:*

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