CVE-2025-39844

Kernel panic via unsynchronized vmemmap page tables

Published Sep 19, 2025 · Updated Sep 19, 2025

Improper page-table synchronization in affected Linux kernel releases allows local users to cause a kernel panic during vmemmap initialization. The optimized vmemmap_populate_compound_pages path installs a new PGD entry only in init_mm.pgd and fails to synchronize other task page tables. Reachability requires 4-level paging and enough persistent memory for vmemmap to span two PGD entries; the bounded consequence is a system crash.

CVSS severity5.5
Medium
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

Improper page-table synchronization in affected Linux kernel releases allows local users to cause a kernel panic during vmemmap initialization. The optimized vmemmap_populate_compound_pages path installs a new PGD entry only in init_mm.pgd and fails to synchronize other task page tables. Reachability requires 4-level paging and enough persistent memory for vmemmap to span two PGD entries; the bounded consequence is a system crash.

The record

CVE
CVE-2025-39844
Published
Sep 19, 2025
Updated
Sep 19, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 19, 2025Record 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=5.13
  2. Affected versionversion=8d400913c231bd1da74067255816453f96cd35b0 <469f9d22751472b81eaaf8a27fcdb5a70741c342
  3. Affected versionversion=8d400913c231bd1da74067255816453f96cd35b0 <4f7537772011fad832f83d6848f8eab282545bef
  4. Affected versionversion=8d400913c231bd1da74067255816453f96cd35b0 <6797a8b3f71b2cb558b8771a03450dc3e004e453
  5. Affected versionversion=8d400913c231bd1da74067255816453f96cd35b0 <732e62212f49d549c91071b4da7942ee3058f7a2
  6. Affected versionversion=8d400913c231bd1da74067255816453f96cd35b0 <7cc183f2e67d19b03ee5c13a6664b8c6cc37ff9d
  7. Affected versionversion=8d400913c231bd1da74067255816453f96cd35b0 <eceb44e1f94bd641b2a4e8c09b64c797c4eabc15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.13; version=8d400913c231bd1da74067255816453f96cd35b0 <469f9d22751472b81eaaf8a27fcdb5a70741c342; version=8d400913c231bd1da74067255816453f96cd35b0 <4f7537772011fad832f83d6848f8eab282545bef; version=8d400913c231bd1da74067255816453f96cd35b0 <6797a8b3f71b2cb558b8771a03450dc3e004e453; version=8d400913c231bd1da74067255816453f96cd35b0 <732e62212f49d549c91071b4da7942ee3058f7a2; version=8d400913c231bd1da74067255816453f96cd35b0 <7cc183f2e67d19b03ee5c13a6664b8c6cc37ff9d; version=8d400913c231bd1da74067255816453f96cd35b0 <eceb44e1f94bd641b2a4e8c09b64c797c4eabc15

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
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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