CVE-2022-48909: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-48909 is a connection leak vulnerability discovered in the Linux kernel's net/smc subsystem. The issue occurs when a CLC CONFIRM message, which is crucial for completing a connection, gets discarded after a TCP abort, preventing the server from properly closing the connection (Red Hat Portal).

The vulnerability manifests in a specific execution sequence where after smcrelease and smcconnectwork operations, if the socket state is SMCINIT, a sendclcconfirm is attempted followed by tcpabort(). The issue arises when tcpabort() discards CLC CONFIRM messages still in the TCP send buffer, preventing the connection token from reaching the server side. This results in the server being unable to receive passive close messages, making it impossible for the connection to be properly disconnected (Kernel Commit).

The vulnerability leads to connection leaks in the Linux kernel's net/smc subsystem, which can result in resource exhaustion over time. The issue has been assigned a CVSS v3 score of 5.5 (Moderate) indicating a moderate severity level (Red Hat Portal).

A patch has been developed that implements an active abort of the SMC connection when the state changes to SMCACTIVE after tcpabort(). This solution provides a faster release for connections in affected scenarios, though future discussions may consider adding a timer after smcclosefinal() (Kernel Commit).