# CVE-2026-123200: VRPN through 07.36 Out-of-bounds Write via SENDER_DESCRIPTION/TYPE_DESCRIPTION length index


- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 5 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-x3v7-qh5m-v37c

## What is CVE-2026-123200?

CVE-2026-123200 is a high-severity vulnerability in VRPN, published on 5 Nov 2026. 

### Official description

VRPN through 07.36 contains an out-of-bounds stack write vulnerability in vrpn_Endpoint::handle_sender_message() and handle_type_message() that allows unauthenticated remote peers to write outside a stack buffer via an unchecked length index. Attackers can connect, complete the version-cookie exchange, and send a SENDER_DESCRIPTION or TYPE_DESCRIPTION message with an out-of-range or negative index to crash the process.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-123200?


## How do I fix CVE-2026-123200?

No fix has been published for CVE-2026-123200 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123200 being exploited?

There is no known exploitation of CVE-2026-123200 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123200 and fix it if it is affected.

What it is: CVE-2026-123200 is a high-severity vulnerability in VRPN, published on 5 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123200 in the wild and no public exploit code.

Affected product: VRPN. 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-2026-123200/ (Markdown: https://insights.sbomify.com/CVE-2026-123200/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123200
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123200
- OSV: https://osv.dev/vulnerability/CVE-2026-123200

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123200/
Summaries are generated and may contain mistakes; the official description above is the record.