# CVE-2026-4359: Heap-buffer-over-read in _mongoc_http_send via strstr on non-null-terminated buffer

> A heap-buffer-over-read in the MongoDB C Driver allows attackers to cause application crashes via malformed HTTP responses.

- **Severity:** Low 2.0 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 17 Mar 2026
- **Updated:** 18 Mar 2026
- **Also known as:** DEBIAN-CVE-2026-4359, GHSA-3548-98v9-6pq6, JLSEC-2026-182, OESA-2026-1742, OESA-2026-1743, OESA-2026-1744, OESA-2026-1746, OESA-2026-1747, UBUNTU-CVE-2026-4359

## What is CVE-2026-4359?

CVE-2026-4359 is a low-severity memory corruption vulnerability in MongoDB C Driver, published on 17 Mar 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

A compromised third party cloud server or man-in-the-middle attacker could send a malformed HTTP response and cause a crash in applications using the MongoDB C driver.

Weakness: CWE-158 (Improper Neutralization of Null Byte or NUL Character)

## Which versions are affected by CVE-2026-4359?

It affects 1 product.


Products: Mongodb C Driver.

## How do I fix CVE-2026-4359?

Apply the vendor's patch.

## Is CVE-2026-4359 being exploited?

There is no known exploitation of CVE-2026-4359 in the wild and no public exploit code.

## Other vulnerabilities in MongoDB C Driver

- [CVE-2026-93393](https://insights.sbomify.com/CVE-2026-93393/): Heap overflow via oversized decrypted TLS record sequence in Windows Secure Channel stream (critical 9.2)
- [CVE-2026-6691](https://insights.sbomify.com/CVE-2026-6691/): MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow (high 8.6)
- [CVE-2026-84964](https://insights.sbomify.com/CVE-2026-84964/): Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client (high 8.2)
- [CVE-2024-7553](https://insights.sbomify.com/CVE-2024-7553/): Accessing Untrusted Directory May Allow Local Privilege Escalation (high 7.3)
- [CVE-2026-93395](https://insights.sbomify.com/CVE-2026-93395/): Integer Underflow → Heap Out-of-Bounds Read in `bson_new_from_buffer() (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4359 and fix it if it is affected.

What it is: CVE-2026-4359 is a low-severity memory corruption vulnerability in MongoDB C Driver, published on 17 Mar 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-4359 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-2026-4359/ (Markdown: https://insights.sbomify.com/CVE-2026-4359/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4359
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4359
- OSV: https://osv.dev/vulnerability/CVE-2026-4359

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4359/
Summaries are generated and may contain mistakes; the official description above is the record.