Kernel hang via unbalanced inode unlock
Published May 30, 2023 · Updated Feb 13, 2025
Improper locking in Canonical Ubuntu Linux shiftfs allows local users with high privileges to hang the kernel through object creation. In shiftfs_create_object, an unsupported lower-filesystem operation follows an error path that unlocks the lower-directory inode without first acquiring its lock. Triggering the race requires a shiftfs mount over an incompatible lower filesystem; successful triggering leaves the kernel deadlocked.
Summary
What happened
Improper locking in Canonical Ubuntu Linux shiftfs allows local users with high privileges to hang the kernel through object creation. In shiftfs_create_object, an unsupported lower-filesystem operation follows an error path that unlocks the lower-directory inode without first acquiring its lock. Triggering the race requires a shiftfs mount over an incompatible lower filesystem; successful triggering leaves the kernel deadlocked.
The record
- CVE
- CVE-2023-2612
- Published
- May 30, 2023
- Updated
- Feb 13, 2025
- Vendor
- Canonical
- Product
- Ubuntu
- Classifications
- CWE-667, T1499
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- May 30, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 2025Record 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 <02b47547824b1cd0d55c6744f91886f04de8947e
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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Public exploit references
- GreHack 2023 shiftfs exploitation demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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