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Vulnerability DatabaseCVE-2025-40012
CVE-2025-40012:
Linux Kernel vulnerability analysis and mitigation
Overview
CVE-2025-40012 is a vulnerability discovered in the Linux kernel affecting the SMC (Shared Memory Communication) subsystem. The issue was disclosed on October 20, 2025, and involves a potential use-after-free vulnerability in the smcrxsplice() function (NVD).
Technical details
The vulnerability occurs when smcloregisterdmb() allocates DMB buffers using kzalloc(), which are later passed to getpage() in smcrxsplice(). Since kmalloc memory is not page-backed, this triggers WARNONONCE() in getpage() and prevents holding a refcount on the buffer. This can lead to use-after-free conditions if the memory is released before spliceto_pipe() completes (NVD).
Impact
The vulnerability could potentially result in use-after-free conditions in the Linux kernel's SMC subsystem, which could lead to memory corruption and system instability (NVD).
Mitigation and workarounds
The issue has been resolved by using folioalloc() instead of kzalloc(), ensuring DMBs are page-backed and safe for getpage(). This fix has been implemented in various Linux distributions, with patches available for affected versions (NVD).
Additional resources
Source: This report was generated using AI
Related Linux Kernel vulnerabilities:
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