CVE-2026-23220

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths

The problem occurs when a signed request fails smb2 signature verification

check. In __process_request(), if check_sign_req() returns an error,

set_smb2_rsp_status(work, STATUS_ACCESS_DENIED) is called.

set_smb2_rsp_status() set work->next_smb2_rcv_hdr_off as zero. By resetting

next_smb2_rcv_hdr_off to zero, the pointer to the next command in the chain

is lost. Consequently, is_chained_smb2_message() continues to point to

the same request header instead of advancing. If the header's NextCommand

field is non-zero, the function returns true, causing __handle_ksmbd_work()

to repeatedly process the same failed request in an infinite loop.

This results in the kernel log being flooded with "bad smb2 signature"

messages and high CPU usage.

This patch fixes the issue by changing the return value from

SERVER_HANDLER_CONTINUE to SERVER_HANDLER_ABORT

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References