# CVE-2026-9740: Unbounded recursion in BSONColumn interleaved-reference causes pre-auth stack overflow

> CVE-2026-9740: Unbounded recursion in BSONColumn interleaved-reference causes pre-auth stack overflow. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-9740
Last updated: 2026-07-23T09:10:00Z

- Published: 2026-06-09 22:43 UTC · Updated: 2026-07-23 09:10 UTC · Assigner: mongodb
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS: 0.34%, 28th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-674

## Description

A vulnerability in MongoDB Server's BSON validation logic allows an unauthenticated user to crash the mongod process by sending a specially crafted message. The BSON validator's handling of certain nested binary data structures permits uncontrolled mutual recursion between validation functions, where each re-entry resets internal depth tracking.

## Affected vendors and products

- MongoDB: MongoDB Server

## Tracked companies

- [MongoDB Atlas](https://rewindex.com/company/mongodb-atlas.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-9740)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-9740)
- [https://jira.mongodb.org/browse/SERVER-125063](https://jira.mongodb.org/browse/SERVER-125063)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-9740 · Markdown: https://rewindex.com/cve/CVE-2026-9740.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-9740 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:49:28.915Z