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.
Affected versions
Linux kernel versions
4.4.34,
4.8.10,
4.9
and later are affected. Fixed in
5.4.301,
5.10.246,
5.15.195,
6.1.156,
6.6.112,
6.12.53,
6.17.3,
6.18
and their respective stable series.
References
The following references provide additional information about CVE-2025-40126 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/0bf3dc3a2156f1c5ddaba4b85d09767874634114
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PatchKernel patch commithttps://git.kernel.org/stable/c/41c18baee66134e6ef786eb075c1b6adb22432b0
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PatchKernel patch commithttps://git.kernel.org/stable/c/4fba1713001195e59cfc001ff1f2837dab877efb
Frequently asked questions
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What is CVE-2025-40126?
CVE-2025-40126 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 4.4.34 onward and has been patched in 5.4.301, 5.10.246, 5.15.195 and others. CVE-2025-40126 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2025-40126?
Yes — CVE-2025-40126 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.195 and others. If you are running Linux kernel 4.4.34 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2025-40126 actively exploited?
No — CVE-2025-40126 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.