CVE-2026-1849 Mongod can run out of stack memory when expressions create deeply nested documents
Attackers can cause MongoDB Server to crash by submitting expressions that create deeply nested documents, leading to stack memory exhaustion.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-1849?
CVE-2026-1849 is a high-severity denial of service vulnerability in Mongodb Mongodb, published on 10 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
MongoDB Server may experience an out-of-memory failure while evaluating expressions that produce deeply nested documents. The issue arises in recursive functions because the server does not periodically check the depth of the expression.
Weakness: CWE-674
Which versions are affected by CVE-2026-1849?
1 open source package ship an affected version, including mongodb. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mongodb Bitnami | From 7.0.0 | 7.0.29, 8.0.18, 8.2.2 |
Products include Mongodb Mongodb.
How do I fix CVE-2026-1849?
Upgrade mongodb to a fixed version for your release line: 7.0.29, 8.0.18 or 8.2.2.
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-2026-1849 being exploited?
There is no known exploitation of CVE-2026-1849 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-2026-1849, GHSA-cf58-vmg8-228p, MINI-4jwj-w98w-2v8m, MINI-wgfw-5fqc-c347, UBUNTU-CVE-2026-1849.