Kernel crash via unprotected IPv6 network structure
Published Feb 27, 2025 · Updated Sep 8, 2026
Use-after-free in the Linux kernel IPv6 routing code allows local users to crash the system during network-namespace teardown. The ip6_default_advmss() function reads its network structure without RCU protection, allowing the structure to be freed while the read remains in progress. Exploitation requires race timing between IPv6 TCP processing and namespace teardown, and the documented consequence is service interruption.
Summary
What happened
Use-after-free in the Linux kernel IPv6 routing code allows local users to crash the system during network-namespace teardown. The ip6_default_advmss() function reads its network structure without RCU protection, allowing the structure to be freed while the read remains in progress. Exploitation requires race timing between IPv6 TCP processing and namespace teardown, and the documented consequence is service interruption.
The record
- CVE
- CVE-2025-21765
- Published
- Feb 27, 2025
- Updated
- Sep 8, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-20, T1499
- 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
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=V3.1.5 <*
- 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
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