CVE-2026-120803

MongoDB SBE $locf Window Accumulator Use-After-Free Enables Heap OOB Read and Server Crash

Published Nov 10, 2026 CVSS 4.0 · 7.1 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
First Time appeared Mongodb
Mongodb mongodb Server
Vendors & Products Mongodb
Mongodb mongodb Server
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mongodb
Published
Updated
Nov 10, 2026, 8:02 PM
Reserved
Nov 2, 2026, 10:54 PM
Status
Awaiting Analysis
Published
Nov 10, 2026, 8:18 PM
Modified
Nov 10, 2026, 10:08 PM