udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n — CVE-2026-23439

Summary

CVE-2026-23439 is a advisory from MSRC. udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n Vendor: Microsoft. Severity/Threat: medium. Source updated on 2026-04-18.

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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