# CVE-2023-42799: Buffer overflow due to use of `strcpy` in `parseUrlAddrFromRtspUrlString`

> A malicious game streaming server can trigger a buffer overflow in the Moonlight client library, potentially leading to remote code execution or crashes.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 14 Dec 2023
- **Updated:** 8 Oct 2024
- **Also known as:** GHSA-r8cf-45f4-vf8m

## What is CVE-2023-42799?

CVE-2023-42799 is a high-severity memory corruption vulnerability in moonlight-stream moonlight-common-c, published on 14 Dec 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Moonlight-common-c contains the core GameStream client code shared between Moonlight clients. Moonlight-common-c is vulnerable to buffer overflow starting in commit 50c0a51b10ecc5b3415ea78c21d96d679e2288f9 due to unmitigated usage of unsafe C functions and improper bounds checking. A malicious game streaming server could exploit a buffer overflow vulnerability to crash a moonlight client, or achieve remote code execution (RCE) on the client (with insufficient exploit mitigations or if mitigations can be bypassed). The bug was addressed in commit 02b7742f4d19631024bd766bd2bb76715780004e.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2023-42799?

It affects 7 products.


Products: Moonlight-Stream Moonlight, Moonlight-Stream Moonlight-Common-C, Moonlight-Stream Moonlight Embedded, Moonlight-Stream Moonlight Switch, Moonlight-Stream Moonlight Tv, Moonlight-Stream Moonlight Vita, Moonlight-Stream Moonlight Xbox.

## How do I fix CVE-2023-42799?

No fix has been published for CVE-2023-42799 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-42799 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-42799 exists.

## Other vulnerabilities in moonlight-stream moonlight-common-c

- [CVE-2023-42800](https://insights.sbomify.com/CVE-2023-42800/): Buffer overflow due to use of `strcpy` in `performRtspHandshake` (high 8.8)
- [CVE-2023-42801](https://insights.sbomify.com/CVE-2023-42801/): Stack buffer overflow due to `strcpy` into fixed size buffer in `extractVersionQuadFromString` (high 7.6)
- [CVE-2020-11024](https://insights.sbomify.com/CVE-2020-11024/): Man-in-the-middle attack in Moonlight iOS/tvOS (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-42799 and fix it if it is affected.

What it is: CVE-2023-42799 is a high-severity memory corruption vulnerability in moonlight-stream moonlight-common-c, published on 14 Dec 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-42799 exists.

Affected product: moonlight-stream moonlight-common-c. 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-2023-42799/ (Markdown: https://insights.sbomify.com/CVE-2023-42799/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-42799
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-42799
- OSV: https://osv.dev/vulnerability/CVE-2023-42799

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-42799/
Summaries are generated and may contain mistakes; the official description above is the record.