Kernel memory corruption via fork failure double free
Published Jun 18, 2025 · Updated Aug 5, 2026
A double free in the s390 task-copy path in Linux allows local users to corrupt kernel memory by forcing fork failure. arch_dup_task_struct copies guarded-storage and runtime-instrumentation pointers into the child task, but a failure before copy_thread clears them leaves free_task to release the parent-owned objects again. Exploitation requires local low-privileged access and s390 guarded-storage or runtime-instrumentation facilities; the resulting use-after-free can panic the kernel or enable privilege escalation.
Summary
What happened
A double free in the s390 task-copy path in Linux allows local users to corrupt kernel memory by forcing fork failure. arch_dup_task_struct copies guarded-storage and runtime-instrumentation pointers into the child task, but a failure before copy_thread clears them leaves free_task to release the parent-owned objects again. Exploitation requires local low-privileged access and s390 guarded-storage or runtime-instrumentation facilities; the resulting use-after-free can panic the kernel or enable privilege escalation.
The record
- CVE
- CVE-2022-49990
- Published
- Jun 18, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-415, T1499.004, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 18, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=232b47b3c88af1da737cd7760f247c4ed58168cf
- Affected versionversion=4.14.5 <4.15
- Affected versionversion=4.15
- Affected versionversion=4.4.105 <4.5
- Affected versionversion=4.9.68 <4.10
- Affected versionversion=8d9047f8b967ce6181fd824ae922978e1b055cc0 <13cccafe0edcd03bf1c841de8ab8a1c8e34f77d9
- Affected versionversion=8d9047f8b967ce6181fd824ae922978e1b055cc0 <25a95303b9e513cd2978aacc385d06e6fec23d07
- Affected versionversion=8d9047f8b967ce6181fd824ae922978e1b055cc0 <297ae7e87a87a001dd3dfeac1cb26a42fd929708
- Affected versionversion=8d9047f8b967ce6181fd824ae922978e1b055cc0 <8195e065abf3df84eb0ad2987e76a40f21d1791c
- Affected versionversion=8d9047f8b967ce6181fd824ae922978e1b055cc0 <cacd522e6652fbc2dc0cc6ae11c4e30782fef14b
- Affected versionversion=8d9047f8b967ce6181fd824ae922978e1b055cc0 <fbdc482d43eda40a70de4b0155843d5472f6de62
- Affected versionversion=9e51ee1b76efc7b5e9404010793a39fde0e03cb7
- Affected versionversion=b8e212c599082896a180a18a0c9bd529526590be
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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