CVE-2026-9743: Aggregation sub-pipeline null dereference may allow DoS via crafted getMore
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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-9743?
CVE-2026-9743 has a medium severity rating of 6.5.
How can CVE-2026-9743 be exploited?
CVE-2026-9743 can be exploited by issuing a crafted getMore on a cursor that references a null sub-pipeline, resulting in a denial of service.
What type of vulnerability is CVE-2026-9743?
CVE-2026-9743 is classified as a null pointer dereference vulnerability.
How do I fix CVE-2026-9743?
To fix CVE-2026-9743, update to a patched version of MongoDB that addresses this null dereference issue.
What software is affected by CVE-2026-9743?
CVE-2026-9743 affects MongoDB Server version 8.0.