CVE-2026-103965: Fixed values in MongoDB Server $bucket stage may be misread as field references

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-13 · updated 2026-10-15
Weakness: CWE-94

Description

An issue in MongoDB Server's aggregation framework can cause certain constant values to be handled incorrectly during internal query rewriting. Under certain conditions, an authenticated user with read access may receive field values in aggregation output that the query did not intend to return.

Affected products

MongoDB: from 8.3.0 before 8.3.13; from 8.0 before 8.0.34; from 7.0 before 7.0.45; from 9.0 before 9.0.4 — fixed in 7.0.45, 8.0.34, 8.3.13, 9.0.4

How to fix

Upgrade to a fixed version: MongoDB 7.0.45, 8.0.34, 8.3.13, 9.0.4. Check the vendor advisory for mitigations.

References

https://jira.mongodb.org/browse/SERVER-134618

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