# CVE-2026-106432: Heap buffer overflow via 32-bit string-length truncation in MongoDB PHP Driver

> Heap buffer overflow in MongoDB PHP Driver allows memory corruption or process termination via integer overflow during large string encoding.

- **Severity:** Low 2.0 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/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:** Yes
- **Published:** 8 Oct 2026
- **Updated:** 8 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-106432, UBUNTU-CVE-2026-106432

## What is CVE-2026-106432?

CVE-2026-106432 is a low-severity vulnerability in MongoDB PHP Driver, published on 8 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The BSON encoder in the MongoDB PHP Driver converts a string length to a 32-bit value without validation. When an affected application encodes a string near 4 GiB, the allocation size can wrap while the copy operation uses the original length. The resulting heap buffer overflow can corrupt process memory or terminate the PHP process. Reaching this issue requires a non-default runtime configuration that permits multi-gigabyte values. No MongoDB server interaction is required.

Weakness: CWE-681 (Incorrect Conversion between Numeric Types)

## Which versions are affected by CVE-2026-106432?

It affects 1 product.


Products: Mongodb Php Driver.

## How do I fix CVE-2026-106432?

Apply the vendor's patch.

## Is CVE-2026-106432 being exploited?

There is no known exploitation of CVE-2026-106432 in the wild and no public exploit code.

## Other vulnerabilities in MongoDB PHP Driver

- [CVE-2026-81525](https://insights.sbomify.com/CVE-2026-81525/): Cross-tenant database retargeting via dot/NUL injection in namespace strings in the PHP Driver (high 8.6)
- [CVE-2026-84968](https://insights.sbomify.com/CVE-2026-84968/): Heap out-of-bounds read via corrupt nested BSON in field path error message (medium 6.9)
- [CVE-2026-106436](https://insights.sbomify.com/CVE-2026-106436/): Application denial of service and data truncation via unchecked BSON append failures in MongoDB PHP Driver (medium 6.3)
- [CVE-2026-6811](https://insights.sbomify.com/CVE-2026-6811/): PHP Stack Exhaustion (medium 6.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-106432 and fix it if it is affected.

What it is: CVE-2026-106432 is a low-severity vulnerability in MongoDB PHP Driver, published on 8 Oct 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-2026-106432 in the wild and no public exploit code.

Affected product: MongoDB PHP 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-2026-106432/ (Markdown: https://insights.sbomify.com/CVE-2026-106432/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-106432
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-106432
- OSV: https://osv.dev/vulnerability/CVE-2026-106432

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-106432/
Summaries are generated and may contain mistakes; the official description above is the record.