Linux Kernel up to 6.17.5 memblock_get_current_limit denial of service

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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 5.15.195/6.1.157/6.6.114/6.12.55/6.17.5. This affects the function memblock_get_current_limit. Such manipulation leads to denial of service. This vulnerability is uniquely identified as CVE-2025-40245. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.15.195/6.1.157/6.6.114/6.12.55/6.17.5 and classified as critical. Affected by this issue is the function memblock_get_current_limit. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2025-40245 since 04/16/2025. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 277484 (Linux Distros Unpatched Vulnerability : CVE-2025-40245), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.196, 6.1.158, 6.6.115, 6.12.56 or 6.17.6 eliminates this vulnerability. Applying the patch 25f09699edd360b534ccae16bc276c3b52c471f3/5c3e38a367822f036227dd52bac82dc4a05157e2/b1ec9faef7e36269ca3ec890972a78effbaeb975/90f5f715550e07cd6a51f80fc3f062d832c8c997/8912814f14e298b83df072fecc1f7ed1b63b1b2c/a20b83cf45be2057f3d073506779e52c7fa17f94 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (277484) and CERT Bund (WID-SEC-2025-2747). Once again VulDB remains the best source for vulnerability data.

Affected

  • Debian Linux
  • Google Cloud Platform
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure Linux

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 277484
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-40245

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.15.196/6.1.158/6.6.115/6.12.56/6.17.6
Patch: 25f09699edd360b534ccae16bc276c3b52c471f3/5c3e38a367822f036227dd52bac82dc4a05157e2/b1ec9faef7e36269ca3ec890972a78effbaeb975/90f5f715550e07cd6a51f80fc3f062d832c8c997/8912814f14e298b83df072fecc1f7ed1b63b1b2c/a20b83cf45be2057f3d073506779e52c7fa17f94

Timelineinfo

04/16/2025 CVE reserved
12/04/2025 +232 days Advisory disclosed
12/04/2025 +0 days VulDB entry created
02/24/2026 +82 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40245 (🔒)
GCVE (CVE): GCVE-0-2025-40245
GCVE (VulDB): GCVE-100-334292
CERT Bund: WID-SEC-2025-2747 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 12/04/2025 17:33
Updated: 02/24/2026 05:52
Changes: 12/04/2025 17:33 (58), 12/06/2025 20:34 (2), 01/05/2026 04:18 (7), 02/24/2026 05:52 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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