Memory Corruption Vulnerability in Linux Kernel CDC-ACM Driver

CVE-2025-21704

Summary

A vulnerability in the CDC-ACM driver of the Linux kernel can lead to memory corruption when the control transfer buffer size is not properly checked before access. If the first fragment received is smaller than the expected structure, memory lengths may be read beyond the allocated buffer, resulting in undefined behavior. This issue has been part of the kernel since its early history and can lead to vulnerabilities during the reassembly of fragmented notifications, particularly when devices are accessed by ModemManager. Proper error handling is crucial to prevent exploitation.

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