CVE-2026-72083

A flaw was found in the Linux kernel's iSCSI target core. This use-after-free vulnerability occurs in the core_scsi3_emulate_pro_register_and_move() function. When processing iSCSI TransportIDs, a memory buffer is prematurely unmapped while still being referenced, particularly when the parameter list spans multiple pages. An attacker could potentially exploit this to cause a system crash, leading to a denial of service.

This vulnerability is rated as Important severity because an authenticated remote client can trigger a kernel-level use-after-free condition on an exposed storage target, potentially causing a system crash or privilege escalation. Under default Red Hat Enterprise Linux installations, the kernel LIO SCSI target framework is inactive unless administrators explicitly configure the system to serve block storage over iSCSI. Consequently, hosts acting exclusively as storage initiators or standard servers without active SCSI target configurations remain unexposed to this flaw.

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 flaw on hosts that do not operate as storage target servers, prevent the LIO target kernel modules from loading:

1. Create a configuration file to prevent loading the target modules:

echo "install iscsi_target_mod /bin/true" > /etc/modprobe.d/disable-iscsi_target.conf

echo "install target_core_mod /bin/true" > /etc/modprobe.d/disable-target_core.conf

2. Stop the SCSI target daemon if active:

systemctl stop target.service

Warning: Modifying kernel module loading or stopping target.service requires a service restart or system reboot, and will immediately interrupt active storage connections on systems acting as storage targets.

If the machine must function as an iSCSI target, use network firewall rules to restrict access to the iSCSI target port (TCP port 3260) strictly to authorized initiator hosts.