CVE-2025-40126
Published Nov 12, 2025
Modified Apr 15, 2026
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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References
Other References
https://git.kernel.org/stable/c/0bf3dc3a2156f1c5ddaba4b85d09767874634114
https://git.kernel.org/stable/c/41c18baee66134e6ef786eb075c1b6adb22432b0
https://git.kernel.org/stable/c/4fba1713001195e59cfc001ff1f2837dab877efb
https://git.kernel.org/stable/c/57c278500fce3cd4e1c540700c0b05426a958393
https://git.kernel.org/stable/c/59424dc0d0e044b2eb007686a4724ddd91d57db5
https://git.kernel.org/stable/c/674ff598148a28bae0b5372339de56f2abf0b1d1
https://git.kernel.org/stable/c/7de3a75bbc8465d816336c74d50109e73501efab
https://git.kernel.org/stable/c/9b137f277cc3297044aabd950f589e505d30104c
Frequently Asked Questions
What is CVE-2025-40126? +
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.
How do I check if I'm vulnerable to CVE-2025-40126? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.