Storage I/O hang via R5_Overlap flag race
Published Aug 15, 2026 · Updated Aug 15, 2026
Race condition in Linux kernel md/raid5 from 4.1 allows remote authenticated users to hang storage I/O through concurrent writes. break_stripe_batch_list() replaces the entire sh->dev[i].flags word after raid5_make_request() atomically sets R5_Overlap, erasing the bit without the required wake-up. Reachability requires write access to an affected RAID5-backed filesystem or network storage service; a lost wake-up leaves I/O waiting indefinitely.
Summary
What happened
Race condition in Linux kernel md/raid5 from 4.1 allows remote authenticated users to hang storage I/O through concurrent writes. break_stripe_batch_list() replaces the entire sh->dev[i].flags word after raid5_make_request() atomically sets R5_Overlap, erasing the bit without the required wake-up. Reachability requires write access to an affected RAID5-backed filesystem or network storage service; a lost wake-up leaves I/O waiting indefinitely.
The record
- CVE
- CVE-2026-72420
- Published
- Aug 15, 2026
- Updated
- Aug 15, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-833, T1499
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 15, 2026CVE publishedPublication date reported by the CVE source.
- Aug 15, 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=4.1
- Affected versionversion=fb642b92c267beeefd352af9bc461eac93a7552c <4d919c9b770996365806b6c8d701912d52baa306
- Affected versionversion=fb642b92c267beeefd352af9bc461eac93a7552c <55b77337bdd088c77461588e5ec094421b89911b
- Affected versionversion=fb642b92c267beeefd352af9bc461eac93a7552c <8031b0d02bd221a5f9add4357e291fc2a527b83a
- Affected versionversion=fb642b92c267beeefd352af9bc461eac93a7552c <d684b72dfbd320623ccaab0779aa841190488e7c
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
Your stack
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Your stack
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