# CVE-2026-81530: KMS master key exposure via unredacted credential serialization in driver settings string

> Attackers with log or memory access can recover unmasked KMS credentials from MongoDB C# Driver settings, enabling decryption of protected data.

- **Severity:** Medium 6.8 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Aug 2026
- **Updated:** 28 Aug 2026

## What is CVE-2026-81530?

CVE-2026-81530 is a medium-severity vulnerability in MongoDB C# Driver, published on 27 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A weakness in the client-side encryption configuration surface of the MongoDB C# Driver causes sensitive key-management credential material supplied by the application to be reproduced verbatim in the driver's human-readable diagnostic representation of its client settings, instead of being masked as other secret fields are. A party able to read the application's logs, diagnostic output, or a process memory dump may thereby recover the plaintext credentials and use them to decrypt protected field data.

Weakness: CWE-532 (Insertion of Sensitive Information into Log File)

## Which versions are affected by CVE-2026-81530?

It affects 1 product.


Products: Mongodb C\# Driver.

## How do I fix CVE-2026-81530?

No fix has been published for CVE-2026-81530 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-81530 being exploited?

There is no known exploitation of CVE-2026-81530 in the wild and no public exploit code.

## Other vulnerabilities in MongoDB C# Driver

- [CVE-2026-88026](https://insights.sbomify.com/CVE-2026-88026/): Regular expression injection via unescaped characters in LINQ query translation in MongoDB C# Driver (high 7.1)
- [CVE-2026-81529](https://insights.sbomify.com/CVE-2026-81529/): Connection-option injection via unescaped settings in the canonical MongoDB URL builder (high 7.1)
- [CVE-2026-81527](https://insights.sbomify.com/CVE-2026-81527/): NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translation (medium 6.9)
- [CVE-2022-48282](https://insights.sbomify.com/CVE-2022-48282/): Deserializing compromised object with MongoDB .NET/C# Driver may cause remote code execution (medium 6.6)
- [CVE-2026-88025](https://insights.sbomify.com/CVE-2026-88025/): GridFS data disclosure and deletion via query-operator injection in file IDs in the MongoDB C# Driver (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-81530 and fix it if it is affected.

What it is: CVE-2026-81530 is a medium-severity vulnerability in MongoDB C# Driver, published on 27 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-81530 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-2026-81530/ (Markdown: https://insights.sbomify.com/CVE-2026-81530/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81530
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81530
- OSV: https://osv.dev/vulnerability/CVE-2026-81530

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-81530/
Summaries are generated and may contain mistakes; the official description above is the record.