CVE-2026-1847: MongoDB Server may crash when inserting large documents

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-10 · updated 2026-06-17
Weakness: CWE-770

Description

Inserting certain large documents into a replica set could lead to replica set secondaries not being able to fetch the oplog from the primary. This could stall replication inside the replica set leading to server crash.

Affected products

MongoDB: from 7.0.0 before 7.0.29; from 8.0.0 before 8.0.18; from 8.2.0 before 8.2.4 — fixed in 7.0.29, 8.0.18, 8.2.4

How to fix

Upgrade to a fixed version: MongoDB 7.0.29, 8.0.18, 8.2.4. Check the vendor advisory for mitigations.

References

https://jira.mongodb.org/browse/SERVER-113532

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