Local kernel crash via exiting-task namespace dereference
Published Jan 19, 2025 · Updated Aug 5, 2026
NULL pointer dereference in the SCTP auth_enable sysctl handler in Linux allows local users to crash the kernel during task exit. The handler obtains its network namespace through current->nsproxy even when the exiting task can have a NULL nsproxy, rather than deriving it from table->data. The trigger requires local low-privileged execution and task-exit state; the bounded consequence is a kernel Oops and service interruption.
Summary
What happened
NULL pointer dereference in the SCTP auth_enable sysctl handler in Linux allows local users to crash the kernel during task exit. The handler obtains its network namespace through current->nsproxy even when the exiting task can have a NULL nsproxy, rather than deriving it from table->data. The trigger requires local low-privileged execution and task-exit state; the bounded consequence is a kernel Oops and service interruption.
The record
- CVE
- CVE-2025-21638
- Published
- Jan 19, 2025
- Updated
- Aug 5, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-476, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 19, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
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- Affected versionversion=0 <*
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Published CVSS scores
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Attacks
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Technologies
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