dm-cache mapping-load failure via mismatched array blocks
Published Sep 11, 2026 · Updated Sep 11, 2026
Out-of-bounds read in the Linux dm-array code allows local users with CAP_SYS_ADMIN to disrupt dm-cache using crafted metadata. __load_mappings() accepts a four-byte hint block as an eight-byte mappings block because array_block_check() validates the header only against itself, so element_at() strides beyond the 4,096-byte block. Reachability requires CAP_SYS_ADMIN to load a crafted device-mapper table; the demonstrated consequence is dm-cache mapping-load failure, not data disclosure or code execution.
Summary
What happened
Out-of-bounds read in the Linux dm-array code allows local users with CAP_SYS_ADMIN to disrupt dm-cache using crafted metadata. __load_mappings() accepts a four-byte hint block as an eight-byte mappings block because array_block_check() validates the header only against itself, so element_at() strides beyond the 4,096-byte block. Reachability requires CAP_SYS_ADMIN to load a crafted device-mapper table; the demonstrated consequence is dm-cache mapping-load failure, not data disclosure or code execution.
The record
- CVE
- CVE-2026-89573
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1565.001
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 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=3.9
- Affected versionversion=6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <4538a287bdf5d0f9a379c678e5262b9f5783f547
- Affected versionversion=6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <7bf4b5cb42a4e27f36bcbc6209d82a5da9c0168c
- Affected versionversion=6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <ac4a5eb8b002a0742c938fc98b922e243f53573a
- Affected versionversion=6513c29f44f2cc970c0e9fecfe5a6526c3e73025 <cb409b38b0232ee4385ef55cddcd6fbdd011a8a2
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What is affected?
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
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