# 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.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Feb 2026
- **Updated:** 10 Feb 2026
- **Also known as:** BIT-mongodb-2026-1849, GHSA-cf58-vmg8-228p, MINI-4jwj-w98w-2v8m, MINI-wgfw-5fqc-c347, UBUNTU-CVE-2026-1849

## 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 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-1849?

1 open source package ship an affected version, including mongodb. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mongodb` | Bitnami | From 7.0.0 | 7.0.29, 8.0.18, 8.2.2 |

Products: 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.

## 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](https://insights.sbomify.com/CVE-2025-14847/): MongoDB and MongoDB Server Improper Handling of Length Parameter Inconsistency (high 8.7, exploited in the wild)
- [CVE-2026-82067](https://insights.sbomify.com/CVE-2026-82067/): Auth bypass in MongoDB Server (critical 9.2)
- [CVE-2026-13072](https://insights.sbomify.com/CVE-2026-13072/): MongoDB Improper Input Validation in Compute Mode External Data Processing Leading to Memory Corruption (critical 9.2)
- [CVE-2017-15535](https://insights.sbomify.com/CVE-2017-15535/): Denial of service in n/a (critical 9.1)
- [CVE-2026-18691](https://insights.sbomify.com/CVE-2026-18691/): Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure (critical 9.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-1849 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-1849 in the wild and no public exploit code.

Affected packages and fixed versions:
- mongodb (Bitnami): affected from 7.0.0; fixed in 7.0.29, 8.0.18, 8.2.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-1849/ (Markdown: https://insights.sbomify.com/CVE-2026-1849/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-1849
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-1849
- OSV: https://osv.dev/vulnerability/CVE-2026-1849

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-1849/
Summaries are generated and may contain mistakes; the official description above is the record.