Local kernel warning via invalid LRU insertion
Published Mar 12, 2025 · Updated Sep 8, 2026
Improper folio handling in Linux and Siemens MFP firmware allows local users to trigger a kernel memory-control warning during migration. migrate_device_finalize() passes a folio whose memcg_data was cleared or never set to folio_putback_lru(), incorrectly adding a soon-freed folio to the LRU. The path requires low-privilege local access and HMM device-private migration; no consequence beyond the warning and redundant LRU operation is documented.
Summary
What happened
Improper folio handling in Linux and Siemens MFP firmware allows local users to trigger a kernel memory-control warning during migration. migrate_device_finalize() passes a folio whose memcg_data was cleared or never set to folio_putback_lru(), incorrectly adding a soon-freed folio to the LRU. The path requires low-privilege local access and HMM device-private migration; no consequence beyond the warning and redundant LRU operation is documented.
The record
- CVE
- CVE-2025-21861
- Published
- Mar 12, 2025
- Updated
- Sep 8, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-20, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 12, 2025CVE publishedPublication date reported by the CVE source.
- Sep 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=V3.1.6 <*
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What is affected?
Published CVSS scores
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Attacks
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Technologies
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