CVE-2026-74345

A flaw was found in the Linux kernel's Soft iWARP (siw) component, which handles high-performance data transfer. This vulnerability occurs when the system processes a specially crafted connection request, leading to a 'use-after-free' error. An attacker could exploit this to cause a denial of service (DoS), making the affected system unresponsive.

This vulnerability is rated as having Important impact for Red Hat Enterprise Linux because an unauthenticated remote attacker can cause a denial of service by triggering a kernel crash through a malformed connection request. The Soft iWARP (siw) driver is not loaded by default on standard Red Hat Enterprise Linux installations, restricting exposure to systems configured with software-based RDMA over TCP/IP. Systems that do not use Soft iWARP or do not expose RDMA endpoints to untrusted networks are not susceptible to remote exploitation.

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.

To mitigate this vulnerability, prevent the Software iWARP (siw) kernel module from loading on systems where Software RDMA functionality is not required.

1. Create a configuration file in /etc/modprobe.d/ to disable module loading:

# echo "install siw /bin/true" > /etc/modprobe.d/disable-siw.conf

2. If the module is currently loaded, unload it:

# modprobe -r siw

Caveats: If the module cannot be unloaded because it is actively in use, a system reboot is required for the change to take full effect. Applying this configuration disables all Software iWARP RDMA network capabilities on the system.