CVE-2021-47328
CriticalCVSS 9.8Exploitation Probability (EPSS)
Elevated risk52th percentile - higher than 52% of all known CVEs
Summary
In the Linux kernel, a use-after-free vulnerability in the iSCSI driver (scsi: iscsi) during resets has been fixed. The issue occurs when iscsi_conn_teardown wakes up the EH thread and frees the connection while those threads are still accessing the connection's ehwait field. The fix moves the TMF fields from the connection to the session.
Risk Assessment
The vulnerability could lead to system crashes or potentially arbitrary code execution by an attacker who can trigger an iSCSI session reset. This requires access to the iSCSI infrastructure.
Recommendation
Update the Linux kernel to a version with the fix. Also restrict access to iSCSI sessions to trusted initiators only.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: scsi: iscsi: Fix conn use after free during resets If we haven't done a unbind target call we can race where iscsi_conn_teardown wakes up the EH thread and then frees the conn while those threads are still accessing the conn ehwait. We can only do one TMF per session so this just moves the TMF fields from the conn to the session. We can then rely on the iscsi_session_teardown->iscsi_remove_session->__iscsi_unbind_session call to remove the target and it's devices, and know after that point there is no device or scsi-ml callout trying to access the session.