The vulnerability is a resource exhaustion flaw in the Linux kernel’s SMB server (ksmbd), identified as CWE-911. When a transport allocation fails during a new connection, the active connection counter is incremented but never decremented, causing that slot to be permanently lost. Repeated failures eventually exhaust the connection pool, after which every subsequent connection, including legitimate ones, is rejected with a “Limit the maximum number of connections” error, leading to a denial‑of‑service of the SMB service until the kernel module is reloaded or the system rebooted.

All Linux systems that contain the ksmbd SMB server component in the kernel are affected. No specific kernel version range is listed, so any kernel build that lacks the commit that fixes the active_num_conn leak is vulnerable.

An unauthenticated attacker can trigger the exploit by opening TCP connections to port 445 and sending large packets that force allocation failures. Because the flaw causes a permanent resource leak, the exploitation likelihood is high on exposed servers, and the impact is complete loss of SMB service availability. The issue is not listed in CISA KEV and no EPSS score is available, but the nature of the bug suggests high severity remote denial of service.