Kernel state corruption via misclassified shmem folios
Published Apr 8, 2025 · Updated Sep 8, 2026
State corruption in affected Linux and Siemens MFP controller kernels allows local users to corrupt shmem xarray entries during folio migration. __folio_migrate_mapping() uses folio_test_swapbacked() to choose the entry count, conflating page-cache shmem folios with swap-cache folios and converting a sibling entry into a normal entry during xas_store(). Low-privileged local access is required, and the corrupted mapping state can interrupt system operation without reported data disclosure or modification.
Summary
What happened
State corruption in affected Linux and Siemens MFP controller kernels allows local users to corrupt shmem xarray entries during folio migration. __folio_migrate_mapping() uses folio_test_swapbacked() to choose the entry count, conflating page-cache shmem folios with swap-cache folios and converting a sibling entry into a normal entry during xas_store(). Low-privileged local access is required, and the corrupted mapping state can interrupt system operation without reported data disclosure or modification.
The record
- CVE
- CVE-2025-22015
- Published
- Apr 8, 2025
- Updated
- Sep 8, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-476
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 8, 2025CVE publishedPublication date reported by the CVE source.
- Sep 8, 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.
- Affected versionversion=V3.1.6 <*
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Userspace shmem folio migration reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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