CVE-2026-9749

Using MaxKey() may crash the server

State: Published
Severity: 7.1 High
Published: Jun 9, 2026
Updated: Jun 10, 2026
Reserved: May 27, 2026

Description

This issue can occur when running an aggregation pipeline that uses the internal $exchange stage configured with key-range partitioning and order-preserving delivery. If a single key range produces enough documents to fill its exchange buffer (that is, many results are routed to the same consumer), the server reaches the code path where a full per-consumer buffer is detected but the internal "high watermark" for that key range is not updated as intended.

Scores

CVSS	Score	Vector	Source
4.0	7.1 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	mongodb
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	mongodb

Weaknesses

CWE-617 Reachable assertion

Affected Products

Product	Versions
MongoDB ServerMongoDB	8.3.0 to before 8.3.3Affected 8.2.0 to before 8.2.10Affected 8.0.0 to before 8.0.24Affected 7.0.0 to before 7.0.35Affected

References

https://jira.mongodb.org/browse/SERVER-124031

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