CVE-2026-120803
MongoDB SBE $locf Window Accumulator Use-After-Free Enables Heap OOB Read and Server Crash
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.
| 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 high vulnerabilities affecting mongodb mongodb server are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H