CVE-2026-72086

Technical Description

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

scsi: xen: scsiback: Free the command tag on the TMR submit-failure path

scsiback_device_action() obtains a command tag in

scsiback_get_pend_req() and submits a task-management request with

target_submit_tmr(). When target_submit_tmr() fails it returns < 0 and

scsiback jumps to the err: label, which sends a response but frees

nothing, leaking the tag.

Impact: a pvSCSI guest can leak the command tags of a LUN's session,

stopping the LUN, by issuing VSCSIIF_ACT_SCSI_ABORT or RESET requests

whenever target_submit_tmr() fails.

transport_generic_free_cmd() cannot be used here. By the time

target_submit_tmr() returns an error it has already run

__target_init_cmd() (so se_cmd->cmd_kref is one, not zero), and on its

target_get_sess_cmd() error path it has freed se_cmd->se_tmr_req via

core_tmr_release_req() while leaving SCF_SCSI_TMR_CDB set and the

pointer dangling. Letting the command release run target_free_cmd_mem()

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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