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CVE Record

CVE-2025-40035: Input: uinput - zero-initialize uinput_ff_upload_compat to avoid info leak

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can leak small pieces of kernel stack memory to local userspace through the uinput force-feedback compatibility path. The source describes an information leak caused by uninitialized padding, not code execution. No provided source says it is being exploited in the wild.

Executive priority

Treat this as a scheduled kernel patching item unless uinput is exposed to untrusted local users or containers. Prioritize shared, multi-user, desktop, kiosk, and container-host environments where local userspace boundaries matter.

Technical view

uinput_ff_upload_compat embeds ff_effect_compat twice. ff_effect_compat contains internal padding, including a hole after struct ff_replay. Without zeroing the outer structure, copy_to_user() may expose stack data. The fix initializes ff_up_compat to zero before populating valid fields.

Likely exposure

Exposure is likely limited to Linux systems running affected kernel builds where userspace can reach the uinput compatibility force-feedback upload path. Systems should verify kernel branch, vendor package status, and access to uinput devices.

Exploitation context

The bundle marks KEV as false and provides no cited evidence of active exploitation. The issue is an information disclosure to userspace, which may be useful for weakening kernel memory protections but is not described as a standalone privilege-escalation bug.

Researcher notes

The available evidence identifies the root cause and fix but does not provide CVSS, CWE, exploitability details, or distribution-specific fixed versions. Avoid assuming remote exposure or privilege escalation without additional vendor analysis.

Mitigation direction

  • Update affected Linux kernels through vendor-supported packages.
  • Confirm updates include one of the referenced stable kernel fixes.
  • Restrict /dev/uinput access to trusted users while patching.
  • Review containers or services with uinput device passthrough.
  • Track distribution advisories for fixed package versions.

Validation and detection

  • Inventory Linux hosts and running kernel versions.
  • Check whether vendor kernels include the referenced stable commits.
  • Review permissions and group access for uinput devices.
  • Identify containers or workloads granted uinput device access.
  • Confirm patched systems rebooted into the updated kernel.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2025-40035 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
9Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux2d56f3a32c0e62f99c043d2579840f9731fe5855, 2d56f3a32c0e62f99c043d2579840f9731fe5855, 2d56f3a32c0e62f99c043d2579840f9731fe5855, 2d56f3a32c0e62f99c043d2579840f9731fe5855, 2d56f3a32c0e62f99c043d2579840f9731fe5855, 2d56f3a32c0e62f99c043d2579840f9731fe5855, 2d56f3a32c0e62f99c043d2579840f9731fe5855, 2d56f3a32c0e62f99c043d2579840f9731fe5855unaffected
LinuxLinux2.6.29, 0, 5.4.301, 5.10.246, 5.15.195, 6.1.156, 6.6.112, 6.12.53, 6.17.3, 6.18affected
Weakness

CWE details

No CWE listed

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