Local privilege escalation via stale Geneve link
Published Mar 12, 2025 · Updated Aug 5, 2026
Use-after-free in the Linux kernel Geneve driver allows local users to gain elevated privileges through cross-namespace device creation. The teardown path frees a device from its owning namespace but leaves geneve_dev.next linked in the backend UDP socket namespace, so geneve_find_dev() later reads freed memory. Exploitation requires local low-privileged access and Geneve device operations across namespaces; successful abuse grants elevated system privileges.
Summary
What happened
Use-after-free in the Linux kernel Geneve driver allows local users to gain elevated privileges through cross-namespace device creation. The teardown path frees a device from its owning namespace but leaves geneve_dev.next linked in the backend UDP socket namespace, so geneve_find_dev() later reads freed memory. Exploitation requires local low-privileged access and Geneve device operations across namespaces; successful abuse grants elevated system privileges.
The record
- CVE
- CVE-2025-21858
- Published
- Mar 12, 2025
- Updated
- Aug 5, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 12, 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
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <*
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo