# CVE-2026-18711: Use-After-Free in MongoDB Query Execution Engine Leads to Denial of Service and Potential Memory Disclosure

> Authenticated users can trigger a use-after-free in MongoDB's query engine, causing server crashes or memory disclosure via time-series collections.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/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:** 11 Aug 2026
- **Updated:** 11 Aug 2026
- **Also known as:** BIT-mongodb-2026-18711, GHSA-xv7q-6jr5-mw96, MINI-2v7h-9fhh-pmv9, MINI-6rhf-rhmq-v8h5, MINI-7gf3-2rxf-c47q, MINI-v5gv-4x6h-hc7v, UBUNTU-CVE-2026-18711

## What is CVE-2026-18711?

CVE-2026-18711 is a high-severity use after free vulnerability in Mongodb Mongodb, published on 11 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An issue in MongoDB Server's query execution engine could allow an authenticated user with read and write privileges to cause an internal reference to be used after the underlying memory has been freed, when running certain queries against time-series collections. This could result in a server crash or disclosure of freed memory contents within query results.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-18711?

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 | 7.0.41, 8.0.29, 8.3.8, 9.0.2 |

Products: Mongodb Mongodb.

## How do I fix CVE-2026-18711?

Upgrade mongodb to a fixed version for your release line: 7.0.41, 8.0.29, 8.3.8 or 9.0.2.

## Is CVE-2026-18711 being exploited?

There is no known exploitation of CVE-2026-18711 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-2026-18711 and fix it if it is affected.

What it is: CVE-2026-18711 is a high-severity use after free vulnerability in Mongodb Mongodb, published on 11 Aug 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-2026-18711 in the wild and no public exploit code.

Affected packages and fixed versions:
- mongodb (Bitnami): affected from 7.0.0; fixed in 7.0.41, 8.0.29, 8.3.8, 9.0.2

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-2026-18711/ (Markdown: https://insights.sbomify.com/CVE-2026-18711/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18711
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18711
- OSV: https://osv.dev/vulnerability/CVE-2026-18711

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18711/
Summaries are generated and may contain mistakes; the official description above is the record.