# CVE-2026-88026: Regular expression injection via unescaped characters in LINQ query translation in MongoDB C# Driver

> An authenticated user can manipulate LINQ queries to bypass filters and read unintended database records via regex injection.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/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:** No
- **Published:** 10 Sep 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-j7j2-rrxf-5xvf

## What is CVE-2026-88026?

CVE-2026-88026 is a high-severity vulnerability in MongoDB C# Driver, published on 10 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Improper neutralization of regular-expression metacharacters in the LINQ query translation component of the MongoDB C# Driver can cause a caller-supplied character sequence to alter a regular-expression predicate generated by an affected application. An authenticated user who can influence such a value may cause the application to return records beyond those intended by the original filter.

Weakness: CWE-943 (Improper Neutralization of Special Elements in Data Query Logic)

## Which versions are affected by CVE-2026-88026?

It affects 1 product.


Products: Mongodb C\# Driver.

## How do I fix CVE-2026-88026?

No fix has been published for CVE-2026-88026 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-88026 being exploited?

There is no known exploitation of CVE-2026-88026 in the wild and no public exploit code.

## Other vulnerabilities in MongoDB C# Driver

- [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-2026-81530](https://insights.sbomify.com/CVE-2026-81530/): KMS master key exposure via unredacted credential serialization in driver settings string (medium 6.8)
- [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-2026-88026 and fix it if it is affected.

What it is: CVE-2026-88026 is a high-severity vulnerability in MongoDB C# Driver, published on 10 Sep 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-2026-88026 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-2026-88026/ (Markdown: https://insights.sbomify.com/CVE-2026-88026/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-88026
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-88026
- OSV: https://osv.dev/vulnerability/CVE-2026-88026

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-88026/
Summaries are generated and may contain mistakes; the official description above is the record.