CVE-2026-120809
Heap use-after-free read via yield-time state save in time-series block unpacking
A use-after-free read issue exists in MongoDB’s SBE (Slot-Based Execution) engine when processing aggregation pipelines with $unwind on time-series collections. An internal error in state-preservation logic can cause a value still referenced by downstream stages to have its underlying memory freed prematurely. An authenticated user can craft an aggregation pipeline under specific conditions to trigger this condition, potentially reading recycled server heap memory in query results or crashing the server. This issue is only triggerable when a non-default server parameter related to the SBE engine is enabled.
| CWE | CWE-416 |
| Vendor | mongodb |
| Product | mongodb server |
| Ecosystems | |
| Industries | Technology |
| Published | Nov 10, 2026 |
Get instant alerts for mongodb mongodb server
Be the first to know when new medium vulnerabilities affecting mongodb mongodb server are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H