CVE-2025-40035 Input: uinput - zero-initialize uinput_ff_upload_compat to avoid info leak
A local attacker can read uninitialized kernel stack memory via the uinput interface due to missing zero-initialization in the ff_effect_compat structure.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40035?
CVE-2025-40035 is a vulnerability in Linux, published on 28 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2025-40035?
How do I fix CVE-2025-40035?
Apply the vendor's patch.
Is CVE-2025-40035 being exploited?
There is no known exploitation of CVE-2025-40035 in the wild and no public exploit code.
Sources
Also known as AZL-68852, BELL-CVE-2025-40035, DEBIAN-CVE-2025-40035, GHSA-8c35-rp3g-c86r, ROOT-OS-DEBIAN-11-CVE-2025-40035, ROOT-OS-UBUNTU-2204-CVE-2025-40035 and 2 more.