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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 smc_rx_splice() function (NVD).
Technical details
The vulnerability occurs when smc_lo_register_dmb() allocates DMB buffers using kzalloc(), which are later passed to get_page() in smc_rx_splice(). Since kmalloc memory is not page-backed, this triggers WARN_ON_ONCE() in get_page() and prevents holding a refcount on the buffer. This can lead to use-after-free conditions if the memory is released before splice_to_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 folio_alloc() instead of kzalloc(), ensuring DMBs are page-backed and safe for get_page(). 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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