Local denial of service via netlink retry loop
Published Sep 4, 2025 · Updated Sep 8, 2026
Denial of service in the Linux kernel netlink subsystem allows local users to stall a CPU via a boundary-sized message. In netlink_attachskb, strict less-than and greater-than receive-buffer checks omit equality, so netlink_unicast neither accepts nor sleeps and retries forever. Local low-privileged access is required, and the resulting busy loop produces an RCU CPU stall that can interrupt system availability.
Summary
What happened
Denial of service in the Linux kernel netlink subsystem allows local users to stall a CPU via a boundary-sized message. In netlink_attachskb, strict less-than and greater-than receive-buffer checks omit equality, so netlink_unicast neither accepts nor sleeps and retries forever. Local low-privileged access is required, and the resulting busy loop produces an RCU CPU stall that can interrupt system availability.
The record
- CVE
- CVE-2025-38727
- Published
- Sep 4, 2025
- Updated
- Sep 8, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-835, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 4, 2025CVE publishedPublication date reported by the CVE source.
- Sep 8, 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=V3.1.5 <*
- Affected versionversion=V3.1.6 <*
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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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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