Local kernel compromise via unprotected ndisc socket access
Published Feb 27, 2025 · Updated Sep 8, 2026
Use-after-free in Linux and Siemens GNU/Linux subsystems allows local users to read or alter kernel memory or crash the system. The ndisc_alloc_skb function assigns dev_net_rcu(dev)->ipv6.ndisc_sk as a packet owner without holding RTNL or an RCU read lock, allowing concurrent teardown to free the referenced network object. Exploitation requires low-privilege local access and execution of an IPv6 Neighbor Discovery path; impact remains confined to the affected system.
Summary
What happened
Use-after-free in Linux and Siemens GNU/Linux subsystems allows local users to read or alter kernel memory or crash the system. The ndisc_alloc_skb function assigns dev_net_rcu(dev)->ipv6.ndisc_sk as a packet owner without holding RTNL or an RCU read lock, allowing concurrent teardown to free the referenced network object. Exploitation requires low-privilege local access and execution of an IPv6 Neighbor Discovery path; impact remains confined to the affected system.
The record
- CVE
- CVE-2025-21764
- Published
- Feb 27, 2025
- Updated
- Sep 8, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 27, 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=V3.1.6 <*
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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