CVE-2025-21725

A vulnerability was found in the Linux kernel's Server Message Block (SMB) client implementation, specifically within the Common Internet File System (CIFS) module. The issue arises when the client attempts to process network interface information provided by the server, particularly the LinkSpeed parameter. If the server omits this parameter or provides an unexpected value, the client may attempt to perform a division operation with a zero value, leading to a divide-by-zero error and subsequent kernel crash. This misconfiguration on the server could lead to system failure.

This flaw is rated as having Moderate impact for Red Hat Enterprise Linux because exploitation requires a system to have an active SMB mount connected to an untrusted or misconfigured server, and the resulting divide-by-zero crash only affects system availability without compromising confidentiality or integrity. Under default configurations, CIFS kernel modules are loaded only when mounting remote SMB file shares, limiting the attack surface to environments actively utilizing SMB storage. Triggering the denial-of-service condition occurs during the reading of CIFS interface statistics or debug data from procfs, which necessitates local interaction or established client sessions.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.