CVE-2025-40245

Kernel panic via inflated PFN limits

Published Dec 4, 2025 · Updated Aug 5, 2026

Denial of service in the Linux kernel from 5.12 affects nios2 CONFIG_FLATMEM systems and causes kernel paging failures or panic. On affected boots, arch/nios2/kernel/setup.c leaves memblock.current_limit at MEMBLOCK_ALLOC_ANYWHERE before PFN limits are calculated, so max_low_pfn can exceed max_pfn and available DRAM. Exposure requires a nios2 kernel built with CONFIG_FLATMEM; the resulting invalid mem_map bounds lead to paging failure and kernel panic.

CVSS severityUnavailable
Unscored
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel from 5.12 affects nios2 CONFIG_FLATMEM systems and causes kernel paging failures or panic. On affected boots, arch/nios2/kernel/setup.c leaves memblock.current_limit at MEMBLOCK_ALLOC_ANYWHERE before PFN limits are calculated, so max_low_pfn can exceed max_pfn and available DRAM. Exposure requires a nios2 kernel built with CONFIG_FLATMEM; the resulting invalid mem_map bounds lead to paging failure and kernel panic.

The record

CVE
CVE-2025-40245
Published
Dec 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.12
  2. Affected versionversion=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <25f09699edd360b534ccae16bc276c3b52c471f3
  3. Affected versionversion=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <5c3e38a367822f036227dd52bac82dc4a05157e2
  4. Affected versionversion=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <8912814f14e298b83df072fecc1f7ed1b63b1b2c
  5. Affected versionversion=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <90f5f715550e07cd6a51f80fc3f062d832c8c997
  6. Affected versionversion=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <a20b83cf45be2057f3d073506779e52c7fa17f94
  7. Affected versionversion=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <b1ec9faef7e36269ca3ec890972a78effbaeb975

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.12; version=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <25f09699edd360b534ccae16bc276c3b52c471f3; version=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <5c3e38a367822f036227dd52bac82dc4a05157e2; version=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <8912814f14e298b83df072fecc1f7ed1b63b1b2c; version=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <90f5f715550e07cd6a51f80fc3f062d832c8c997; version=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <a20b83cf45be2057f3d073506779e52c7fa17f94; version=7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae <b1ec9faef7e36269ca3ec890972a78effbaeb975

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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