A use-after-free issue exists in MongoDB’s SBE (Slot-Based Execution) implementation of a window function accumulator used by certain $setWindowFields aggregation pipelines. Under specific conditions, the accumulator can retain a dangling pointer to memory that has since been freed. When this stale pointer is later dereferenced during serialization of the carried-forward value, it can result in a heap out-of-bounds read that may expose adjacent heap contents and crash the mongod server. An authenticated user with readWrite privileges on a database can trigger this issue by crafting a specific aggregation pipeline.
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History

Tue, 10 Nov 2026 20:15:00 +0000

Type Values Removed Values Added
Description A use-after-free issue exists in MongoDB’s SBE (Slot-Based Execution) implementation of a window function accumulator used by certain $setWindowFields aggregation pipelines. Under specific conditions, the accumulator can retain a dangling pointer to memory that has since been freed. When this stale pointer is later dereferenced during serialization of the carried-forward value, it can result in a heap out-of-bounds read that may expose adjacent heap contents and crash the mongod server. An authenticated user with readWrite privileges on a database can trigger this issue by crafting a specific aggregation pipeline.
Title MongoDB SBE $locf Window Accumulator Use-After-Free Enables Heap OOB Read and Server Crash
Weaknesses CWE-416
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H'}

cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: mongodb

Published:

Updated: 2026-11-10T20:02:53.682Z

Reserved: 2026-11-02T22:54:09.274Z

Link: CVE-2026-120803

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-10T20:18:50.420

Modified: 2026-11-10T20:18:50.420

Link: CVE-2026-120803

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses