Local denial of service via PAT memory leak
Published May 19, 2024 · Updated May 12, 2026
Memory leak in x86 PAT handling in Linux allows local users to exhaust kernel memory by creating private COW mappings. After a write fault replaces a PTE with an anonymous folio, follow_phys() returns the wrong address or fails, so untrack_pfn() skips or misdirects free_pfn_range() and leaks memory. Exploitation requires local low-privilege access on an x86 system and a private writable mapping that undergoes copy-on-write; the demonstrated path uses an io_uring ring and memory pressure.
Summary
What happened
Memory leak in x86 PAT handling in Linux allows local users to exhaust kernel memory by creating private COW mappings. After a write fault replaces a PTE with an anonymous folio, follow_phys() returns the wrong address or fails, so untrack_pfn() skips or misdirects free_pfn_range() and leaks memory. Exploitation requires local low-privilege access on an x86 system and a private writable mapping that undergoes copy-on-write; the demonstrated path uses an io_uring ring and memory pressure.
The record
- CVE
- CVE-2024-35877
- Published
- May 19, 2024
- Updated
- May 12, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-401, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 19, 2024CVE publishedPublication date reported by the CVE source.
- May 12, 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?
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- Affected versionversion=0 <*
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- Upstream io_uring COW reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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