CVE-2025-40126
Unknown Unknown - Not Provided
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Publication date: 2025-11-12

Last updated on: 2025-11-12

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: sparc: fix accurate exception reporting in copy_{from_to}_user for UltraSPARC The referenced commit introduced exception handlers on user-space memory references in copy_from_user and copy_to_user. These handlers return from the respective function and calculate the remaining bytes left to copy using the current register contents. This commit fixes a couple of bad calculations. This will fix the return value of copy_from_user and copy_to_user in the faulting case. The behaviour of memcpy stays unchanged.
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Meta Information
Published
2025-11-12
Last Modified
2025-11-12
Generated
2026-06-16
AI Q&A
2025-11-13
EPSS Evaluated
2026-06-14
NVD
CVE-2025-40126
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability relates to the Linux kernel on UltraSPARC systems, where exception handlers in the functions copy_from_user and copy_to_user did not correctly calculate the remaining bytes to copy after a fault occurred. This caused inaccurate exception reporting and incorrect return values from these functions. The issue has been fixed to ensure accurate exception handling and correct return values during user-space memory operations.

Impact Analysis

The vulnerability could lead to incorrect handling of exceptions during user-space memory copying operations, potentially causing software relying on these functions to behave unexpectedly or incorrectly handle errors. This might affect system stability or security on UltraSPARC Linux systems if the return values from these functions are used for critical decision-making.

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