Security Flaw in the Linux Kernel Affecting Connectible Sockets

CVE-2025-21854

What is CVE-2025-21854?

The Linux kernel features a vulnerability related to connectible sockets where an unconnected socket may inadvertently lose its assigned transport. This edge case, if not properly managed, can lead to null pointer dereferences. Specifically, the sockmap is not intended to support listening vsocks, yet a failed connect attempt might leave a listening vsock erroneously associated with a transport, resulting in potential crashes or misbehavior during execution. This flaw needs addressing to ensure that sockmap only permits established connections, aligning its functionality with that of AF_INET and AF_UNIX protocols.

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