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CVE-2025-40245
nios2: ensure that memblock.current_limit is set when setting pfn limits
Description

In the Linux kernel, the following vulnerability has been resolved: nios2: ensure that memblock.current_limit is set when setting pfn limits On nios2, with CONFIG_FLATMEM set, the kernel relies on memblock_get_current_limit() to determine the limits of mem_map, in particular for max_low_pfn. Unfortunately, memblock.current_limit is only default initialized to MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading to situations where max_low_pfn can erroneously exceed the value of max_pfn and, thus, the valid range of available DRAM. This can in turn cause kernel-level paging failures, e.g.: [ 76.900000] Unable to handle kernel paging request at virtual address 20303000 [ 76.900000] ea = c0080890, ra = c000462c, cause = 14 [ 76.900000] Kernel panic - not syncing: Oops [ 76.900000] ---[ end Kernel panic - not syncing: Oops ]--- This patch fixes this by pre-calculating memblock.current_limit based on the upper limits of the available memory ranges via adjust_lowmem_bounds, a simplified version of the equivalent implementation within the arm architecture.

INFO

Published Date :

Dec. 4, 2025, 4:16 p.m.

Last Modified :

Dec. 4, 2025, 5:15 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2025-40245 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Ensure memblock.current_limit is correctly set to prevent kernel paging failures.
  • Apply the provided kernel patch.
  • Pre-calculate memblock.current_limit.
  • Adjust low memory bounds.
  • Update the Linux kernel.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-40245.

URL Resource
https://git.kernel.org/stable/c/25f09699edd360b534ccae16bc276c3b52c471f3
https://git.kernel.org/stable/c/5c3e38a367822f036227dd52bac82dc4a05157e2
https://git.kernel.org/stable/c/8912814f14e298b83df072fecc1f7ed1b63b1b2c
https://git.kernel.org/stable/c/90f5f715550e07cd6a51f80fc3f062d832c8c997
https://git.kernel.org/stable/c/a20b83cf45be2057f3d073506779e52c7fa17f94
https://git.kernel.org/stable/c/b1ec9faef7e36269ca3ec890972a78effbaeb975
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-40245 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-40245 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-40245 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-40245 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Dec. 04, 2025

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: nios2: ensure that memblock.current_limit is set when setting pfn limits On nios2, with CONFIG_FLATMEM set, the kernel relies on memblock_get_current_limit() to determine the limits of mem_map, in particular for max_low_pfn. Unfortunately, memblock.current_limit is only default initialized to MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading to situations where max_low_pfn can erroneously exceed the value of max_pfn and, thus, the valid range of available DRAM. This can in turn cause kernel-level paging failures, e.g.: [ 76.900000] Unable to handle kernel paging request at virtual address 20303000 [ 76.900000] ea = c0080890, ra = c000462c, cause = 14 [ 76.900000] Kernel panic - not syncing: Oops [ 76.900000] ---[ end Kernel panic - not syncing: Oops ]--- This patch fixes this by pre-calculating memblock.current_limit based on the upper limits of the available memory ranges via adjust_lowmem_bounds, a simplified version of the equivalent implementation within the arm architecture.
    Added Reference https://git.kernel.org/stable/c/25f09699edd360b534ccae16bc276c3b52c471f3
    Added Reference https://git.kernel.org/stable/c/5c3e38a367822f036227dd52bac82dc4a05157e2
    Added Reference https://git.kernel.org/stable/c/8912814f14e298b83df072fecc1f7ed1b63b1b2c
    Added Reference https://git.kernel.org/stable/c/90f5f715550e07cd6a51f80fc3f062d832c8c997
    Added Reference https://git.kernel.org/stable/c/a20b83cf45be2057f3d073506779e52c7fa17f94
    Added Reference https://git.kernel.org/stable/c/b1ec9faef7e36269ca3ec890972a78effbaeb975
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
No CVSS metrics available for this vulnerability.