Memory Management Vulnerability in Linux Kernel Affecting Multiple Versions

CVE-2025-39775

What is CVE-2025-39775?

This vulnerability in the Linux kernel relates to memory management during the mremap() process. When a userfaultd instance is registered on a Virtual Memory Area (VMA) that encompasses at least one Page Middle Directory (PMD), a warning may be triggered under certain conditions. This situation arises when a page table move fails due to allocation errors, leading to an undesired warning message without compromising the integrity of the kernel's operations. The issue is mitigated by implementing a check prior to the PMD sanity verification, ensuring smoother memory management and improved responsiveness during recovery operations.

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