The Linux kernel’s ksmbd component can enter an infinite loop when a signed SMB2 request fails signature verification. The bug resets the next request offset to zero while still marking the message as chained, causing the same failed request to be processed repeatedly. This results in kernel log flooding with “bad smb2 signature” entries and a spike in CPU usage, effectively a denial‑of‑service condition. The patch changes the return value to abort, terminating the processing loop immediately.

The issue exists in Linux kernel builds starting with version 6.6, including release candidates 6.6‑rc6 and 6.6‑rc7, and any system that ships with the ksmbd module and runs a kernel derived from 6.6 or earlier until the patch is applied. All Linux installations that enable the ksmbd server are potentially affected.

The CVSS score of 5.5 indicates moderate severity, and the EPSS of less than 1 % suggests a low likelihood of exploitation in the wild. The vulnerability requires an attacker to interact with the SMB2 service and to send signed requests that fail verification, so the attack vector is network‑based. Because the flaw consumes CPU rather than compromising confidentiality or integrity, its impact is limited to denial of service. The vulnerability is not listed in CISA’s KEV catalog, reflecting the current low exploitation risk.