CVE-2025-40124: Linux kernel · sparc: fix accurate exception reporting in copy_{from_to}_user for UltraSPARC III
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel source code. Users and administrators should apply the official kernel updates that include this patch to resolve the issue. Since this is a kernel-level fix, upgrading to the patched kernel version is the recommended remediation. Patch status is not explicitly confirmed in the provided data; therefore, check the official Linux kernel advisories or vendor updates for the exact fixed versions and apply them accordingly.
Description
A vulnerability in the Linux kernel related to the sparc architecture has been resolved. The issue involved inaccurate exception reporting in the copy_from_user and copy_to_user functions for UltraSPARC III processors. Specifically, a BUG_ON in ext4 code with large folios was triggered due to copy_from_user returning values larger than the size to be copied, causing __copy_from_iter to return impossible values. The root cause was improper masking of register %o2 during the bulk copy loop in exception handlers. This flaw affected the correctness of return values in fault cases but did not change memcpy behavior.
References
- nvd.nist.gov/vuln/detail/CVE-2025-40124 (opens in a new tab)
- git.kernel.org/stable/c/1198077606aeffb102587c6ea079ce99641c99d4 (opens in a new tab)
- git.kernel.org/stable/c/1857cdca12c4aff58bf26a7005a4d02850c29927 (opens in a new tab)
- git.kernel.org/stable/c/47b49c06eb62504075f0f2e2227aee2e2c2a58b3 (opens in a new tab)
- git.kernel.org/stable/c/5ef9c94d7110e90260c06868cf1dcf899b9f25ee (opens in a new tab)
- git.kernel.org/stable/c/91eda032eb16e5d2be27c95584665bc555bb5a90 (opens in a new tab)
- git.kernel.org/stable/c/dc766c4830a7e1e1ee9d7f77d4ab344f2eb23c8e (opens in a new tab)
- git.kernel.org/stable/c/e50377c6b3f278c9f3ef017ffce17f5fcc9dace4 (opens in a new tab)
- git.kernel.org/stable/c/fdd43fe6d286f27b826572457a89c926f97e2d3a (opens in a new tab)