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CVE-2025-39845

5.5 · MEDIUM
Published Sep 19, 2025 linux CWE-401 EPSS 0.15% (5th pctl)

Overview

CVE-2025-39845 is a medium-severity vulnerability affecting linux linux_kernel. It was published on September 19, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()

Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure

page tables are properly synchronized when calling p*d_populate_kernel().

For 5-level paging, synchronization is performed via

pgd_populate_kernel(). In 4-level paging, pgd_populate() is a no-op, so

synchronization is instead performed at the P4D level via

p4d_populate_kernel().

This fixes intermittent boot failures on systems using 4-level paging and

a large amount of persistent memory:

BUG: unable to handle page fault for address: ffffe70000000034

#PF: supervisor write access in kernel mode

#PF: error_code(0x0002) - not-present page

PGD 0 P4D 0

Oops: 0002 [#1] SMP NOPTI

RIP: 0010:__init_single_page+0x9/0x6d

Call Trace:

<TASK>

__init_zone_device_page+0x17/0x5d

memmap_init_zone_device+0x154/0x1bb

pagemap_range+0x2e0/0x40f

memremap_pages

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

Vendor Product Versions Status
linux linux_kernel >= 5.13, < 5.15.192 Affected

Frequently Asked Questions

What is CVE-2025-39845?

CVE-2025-39845 is a medium-severity vulnerability affecting linux linux_kernel. It was published on September 19, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-39845?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2025-39845?

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2025-39845?

CyberStrike's AI-powered security agents can automatically detect CVE-2025-39845 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.