CVE-2026-9740 Unbounded recursion in BSONColumn interleaved-reference causes pre-auth stack overflow
An unauthenticated attacker can crash the MongoDB server by sending a specially crafted message that triggers unbounded recursion in BSON validation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-9740?
CVE-2026-9740 is a high-severity denial of service vulnerability in Mongodb Mongodb, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-674
Which versions are affected by CVE-2026-9740?
1 open source package ship an affected version, including mongodb. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mongodb Bitnami | From 7.0.0 | 7.0.35, 8.0.24, 8.2.10, 8.3.3 |
Products include Mongodb Mongodb.
How do I fix CVE-2026-9740?
Upgrade mongodb to a fixed version for your release line: 7.0.35, 8.0.24, 8.2.10 or 8.3.3.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-9740 being exploited?
There is no known exploitation of CVE-2026-9740 in the wild and no public exploit code.
Other vulnerabilities in Mongodb Mongodb
- CVE-2025-14847 MongoDB and MongoDB Server Improper Handling of Length Parameter Inconsistency
- CVE-2026-82067 Auth bypass in MongoDB Server
- CVE-2026-13072 MongoDB Improper Input Validation in Compute Mode External Data Processing Leading to Memory Corruption
- CVE-2017-15535 Denial of service in n/a
- CVE-2026-18691 Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure
Sources
Also known as BIT-mongodb-2026-9740, GHSA-wvrr-4w4f-3v54, MINI-2m67-6vm2-8xxq, MINI-9xfw-2fmp-pgvm, MINI-mpj8-55c8-92cv, MINI-wc83-qfw5-f7wp and 1 more.