CVE-2026-23193

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

scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count()

In iscsit_dec_session_usage_count(), the function calls complete() while holding the sess->session_usage_lock. Similar to the connection usage count logic, the waiter signaled by complete() (e.g., in the session release path) may wake up and free the iscsit_session structure immediately.

This creates a race condition where the current thread may attempt to execute spin_unlock_bh() on a session structure that has already been deallocated, resulting in a KASAN slab-use-after-free.

To resolve this, release the session_usage_lock before calling complete() to ensure all dereferences of the sess pointer are finished before the waiter is allowed to proceed with deallocation.

A use after free can occur in the iSCSI target session usage count logic because iscsit_dec_session_usage_count can call complete while holding session_usage_lock. A waiting thread in the session release path can wake up and free the session structure immediately after the completion is signaled. The current thread may then attempt to unlock or otherwise access fields in a session object that has already been deallocated which can trigger a slab use after free and crash the kernel. The attack surface is adjacent network because iSCSI targets are typically reachable only inside storage or data center networks. Impact can be denial of service. A conservative assessment also considers potential confidentiality and integrity impact due to kernel memory corruption from a use after free.

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 issue, prevent module iscsi_target_mod from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.