Bug 2406751 (CVE-2025-40035)

Summary: CVE-2025-40035 kernel: Input: uinput - zero-initialize uinput_ff_upload_compat to avoid info leak
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-10-28 12:03:35 UTC 
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.
Comment 1 Jon Moroney 2025-10-28 18:41:33 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025102811-CVE-2025-40035-9c37@gregkh/T