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.
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Fixes
Solution
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References
| Link | Providers |
|---|---|
| https://jira.mongodb.org/browse/SERVER-132279 |
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History
Tue, 10 Nov 2026 20:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | Heap use-after-free read via yield-time state save in time-series block unpacking | |
| Weaknesses | CWE-416 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: mongodb
Published:
Updated: 2026-11-10T20:08:12.615Z
Reserved: 2026-11-02T22:54:19.524Z
Link: CVE-2026-120809
No data.
Status : Received
Published: 2026-11-10T20:18:51.323
Modified: 2026-11-10T20:18:51.323
Link: CVE-2026-120809
No data.
OpenCVE Enrichment
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Weaknesses