Heap use-after-free read via yield-time state save in time-series block unpacking

published 2026-11-10 yesterday modified 2026-11-10 yesterday also EUVD-2026-122900

cvss: 6.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

MongoDB MongoDB Server 8.0.37, 8.3.16, 9.0.7

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Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.1	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N
CNA	3.1	6.8	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
CNA	4.0	6.1	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

MongoDB MongoDB Server

Classification

Weakness

CWE-416 Use After Free

Technology feeds

MongoDB rss critical rss

References

jira.mongodb.org /browse/SERVER-132279

Sources

CVE List CVE-2026-120809
NVD CVE-2026-120809

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