# CVE-2026-114646: NoSQL command injection via mismatched raw BSON length prefix written verbatim to the wire


- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 22 Oct 2026
- **Updated:** 22 Oct 2026
- **Also known as:** GHSA-5chr-phc4-wcj2

## What is CVE-2026-114646?

CVE-2026-114646 is a medium-severity vulnerability in MongoDB C# Driver, published on 22 Oct 2026. 

### Official description

A data-validation flaw exists in the BSON handling and binary serialization path of the MongoDB C# Driver. When an application constructs a raw or lazy BSON document object from externally supplied binary data, the driver does not verify that the size quantity declared inside that data matches the amount of data actually provided, and it copies the data onto the wire unchanged. An unauthenticated party who can supply binary content to such an application can thereby cause additional elements to be inserted into, or existing elements to be removed from, the database command the application issues, without needing any database credentials of their own. This can result in unauthorized modification of stored data and disclosure of data outside the intended scope of the application's request, bounded by the database privileges the application itself holds.

Weakness: CWE-130 (Improper Handling of Length Parameter Inconsistency)

## Which versions are affected by CVE-2026-114646?


## How do I fix CVE-2026-114646?

No fix has been published for CVE-2026-114646 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-114646 being exploited?

There is no known exploitation of CVE-2026-114646 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-114646 and fix it if it is affected.

What it is: CVE-2026-114646 is a medium-severity vulnerability in MongoDB C# Driver, published on 22 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-114646 in the wild and no public exploit code.

Affected product: MongoDB C# Driver. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-114646/ (Markdown: https://insights.sbomify.com/CVE-2026-114646/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-114646
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-114646
- OSV: https://osv.dev/vulnerability/CVE-2026-114646

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-114646/
Summaries are generated and may contain mistakes; the official description above is the record.