CVE-2026-74524
Received Received - Intake

Memory Hot-Remove Page-Table Walk Flaw in Linux Kernel

Vulnerability report for CVE-2026-74524, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: riscv: mm: Fix out-of-bounds page-table walk during memory hot-remove remove_pud_mapping() and remove_p4d_mapping() obtain a child table base with pud_offset(p4dp, 0) and p4d_offset(pgd, 0), then add the index for addr. RISC-V folds page-table levels at runtime. When a level is folded, its offset helper returns the parent entry itself, but the index can still be nonzero. Adding it walks past the parent table. Sv48 folds P4D, while Sv39 folds both P4D and PUD, so memory hot-remove can descend into unrelated memory and pass an invalid page to __free_pages(). This can trigger: kernel BUG at include/linux/mm.h:1810! VM_BUG_ON_PAGE(page_ref_count(page) == 0) arch_remove_memory+0x1e/0x5c try_remove_memory+0x15e/0x200 remove_memory+0x24/0x3c Only add the index when the corresponding page-table level is enabled, matching p4d_offset() and pud_offset().

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Meta Information

Published
2026-08-15
Last Modified
2026-08-17
Generated
2026-09-04
AI Q&A
2026-08-15
EPSS Evaluated
2026-09-03
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves an out-of-bounds page-table walk during memory hot-remove operations on RISC-V systems. The issue occurs when remove_pud_mapping() and remove_p4d_mapping() incorrectly calculate page-table offsets, leading to memory access beyond valid bounds. This happens because RISC-V dynamically folds page-table levels, and the offset helpers may return parent entries with non-zero indices, causing invalid memory access.

Detection Guidance

This vulnerability affects the Linux kernel's memory management on RISC-V systems. Detection requires checking kernel logs for BUG messages or VM_BUG_ON_PAGE errors during memory hot-remove operations. Monitor system logs for crashes or kernel panics related to page-table handling.

Impact Analysis

This vulnerability can cause kernel crashes due to invalid memory access during memory hot-remove operations. It may trigger kernel bugs like BUG at mm.h or VM_BUG_ON_PAGE, leading to system instability or denial of service. Systems using RISC-V with memory hot-remove enabled are particularly affected.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it is a low-level kernel memory management issue. Standards like GDPR and HIPAA focus on data protection and privacy, while this issue relates to memory hot-remove operations in the Linux kernel.

Mitigation Strategies

Apply the latest Linux kernel patches that fix this issue. Avoid performing memory hot-remove operations until the kernel is updated. If hot-remove is necessary, ensure the system is not in a vulnerable state (e.g., disable memory hot-remove temporarily).

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