CVE-2026-98174

A flaw was found in the Linux kernel's SMB client subsystem. Missing list initialization and a race condition during connection reconnect operations can lead to a null-pointer dereference or list corruption. This flaw allows reconnection events, such as during network instability or server failover, to cause a kernel crash, resulting in a Denial of Service (DoS).

A race in the SMB client reconnect path can add the same TCP_Server_Info.rlist node to a reconnect list more than once. The rlist node is also not initialized when a TCP session is allocated. Duplicate list insertion can corrupt Linux list metadata and may cause invalid pointer dereferences or a kernel crash during reconnect processing. A remote SMB server or an attacker able to disrupt SMB transport can potentially induce reconnect activity. Reliable triggering requires a timing window between concurrent cifsd threads. For the CVSS the PR:N because no local account or privileges on the client are required when the victim has an SMB client mount connected to an attacker controlled or reachable SMB server. Impact is at least network reachable denial of service via kernel crash. The paranoid assessment includes limited confidentiality and integrity impact because corrupted list metadata is a memory corruption condition. SMB client mounts are commonly used in internal enterprise networks. Practical exploitation normally requires access to the SMB server path or the ability to interfere with the SMB connection.

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.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.