LSM bypass via uncleared S_PRIVATE flag
Published Jul 25, 2025 · Updated Aug 5, 2026
LSM bypass in Linux kernel secretmem allows local users to read or alter protected memory through secretmem file descriptors. The secretmem inode creation path leaves S_PRIVATE set after alloc_anon_inode(), so SELinux and Smack treat the inode as private and skip access and attribute checks. A low-privileged local process must create or receive a secretmem descriptor; the bypass permits unmediated mapping, reading, writing, truncation, or ownership and mode changes to policy-protected contents.
Summary
What happened
LSM bypass in Linux kernel secretmem allows local users to read or alter protected memory through secretmem file descriptors. The secretmem inode creation path leaves S_PRIVATE set after alloc_anon_inode(), so SELinux and Smack treat the inode as private and skip access and attribute checks. A low-privileged local process must create or receive a secretmem descriptor; the bypass permits unmediated mapping, reading, writing, truncation, or ownership and mode changes to policy-protected contents.
The record
- CVE
- CVE-2025-38396
- Published
- Jul 25, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 25, 2025CVE publishedPublication date reported by the CVE source.
- 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?
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- Affected versionversion=2bfe15c5261212130f1a71f32a300bcf426443d4 <66d29d757c968d2bee9124816da5d718eb352959
- Affected versionversion=2bfe15c5261212130f1a71f32a300bcf426443d4 <6ca45ea48530332a4ba09595767bd26d3232743b
- Affected versionversion=2bfe15c5261212130f1a71f32a300bcf426443d4 <cbe4134ea4bc493239786220bd69cb8a13493190
- Affected versionversion=2bfe15c5261212130f1a71f32a300bcf426443d4 <e3eed01347721cd7a8819568161c91d538fbf229
- Affected versionversion=2bfe15c5261212130f1a71f32a300bcf426443d4 <f94c422157f3e43dd31990567b3e5d54b3e5b32b
- Affected versionversion=6.0
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
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Technologies
Your stack
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Your stack
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