Kernel-memory disclosure via stale time-namespace vvar page
Published Feb 17, 2023 · Updated Mar 12, 2025
Use-after-free in io_uring in Linux Kernel 5.6 through 5.10.161 allows local users to read kernel memory through a stale vvar mapping. timens_install treats a process as single-threaded without counting io_uring workers, so a fault can map a time namespace's vvar page that remains after the namespace frees it. A low-privileged local process must create the io_uring worker and time-namespace race; the exposed mapping is read-only, so the documented consequence is kernel-memory disclosure.
Summary
What happened
Use-after-free in io_uring in Linux Kernel 5.6 through 5.10.161 allows local users to read kernel memory through a stale vvar mapping. timens_install treats a process as single-threaded without counting io_uring workers, so a fault can map a time namespace's vvar page that remains after the namespace frees it. A low-privileged local process must create the io_uring worker and time-namespace race; the exposed mapping is read-only, so the documented consequence is kernel-memory disclosure.
The record
- CVE
- CVE-2023-23586
- Published
- Feb 17, 2023
- Updated
- Mar 12, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-416
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 17, 2023CVE publishedPublication date reported by the CVE source.
- Mar 12, 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=5.6 <=5.10.161
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
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Your stack
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