CVE-2025-68745 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Clear cmds after chip reset
Commit aefed3e5548f ("scsi: qla2xxx: target: Fix offline port handling and host reset handling") caused two problems:
1. Commands sent to FW, after chip reset got stuck and never freed as FW is not going to respond to them anymore.
2. BUG_ON(cmd->sg_mapped) in qlt_free_cmd(). Commit 26f9ce53817a ("scsi: qla2xxx: Fix missed DMA unmap for aborted commands") attempted to fix this, but introduced another bug under different circumstances when two different CPUs were racing to call qlt_unmap_sg() at the same time: BUG_ON(!valid_dma_direction(dir)) in dma_unmap_sg_attrs().
So revert "scsi: qla2xxx: Fix missed DMA unmap for aborted commands" and partially revert "scsi: qla2xxx: target: Fix offline port handling and host reset handling" at __qla2x00_abort_all_cmds.
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Analysis
by VulDB Data Team • 05/24/2026
The vulnerability CVE-2025-68745 affects the Linux kernel's qla2xxx SCSI driver which manages QLogic Fibre Channel host bus adapters. This issue stems from improper handling of commands during chip reset operations, creating a critical race condition that can lead to system instability and potential denial of service. The problem manifests when commands are sent to the firmware after a chip reset operation, causing them to become permanently stuck in the system without proper cleanup. The root cause lies in the driver's inability to properly manage command state transitions during hardware reset scenarios, particularly affecting the target mode functionality of the QLogic adapters.
The technical flaw involves a complex interaction between multiple kernel subsystems and memory management components. When a chip reset occurs, commands that were previously sent to the firmware remain in an inconsistent state where they are neither acknowledged nor properly freed by the system. This creates a memory leak scenario where command structures accumulate in the kernel's command queue, eventually leading to resource exhaustion. The original fix attempt in commit 26f9ce53817a aimed to address missed DMA unmap operations for aborted commands but inadvertently introduced a new race condition. This secondary bug occurs when multiple CPU cores simultaneously attempt to call the qlt_unmap_sg() function, triggering a DMA validation check that fails under concurrent access conditions.
The operational impact of this vulnerability extends beyond simple resource consumption, potentially leading to complete system lockups or crashes. Attackers could exploit this weakness by repeatedly triggering chip reset scenarios through malicious SCSI commands or by forcing system resets in targeted environments. The race condition between CPU cores during DMA unmap operations creates unpredictable system behavior that may manifest as kernel oops messages, memory corruption, or complete system hangs. This vulnerability affects systems running Linux kernels that include the affected qla2xxx driver components, particularly those utilizing QLogic Fibre Channel hardware in server or storage environments where reliable command processing is critical.
Mitigation strategies should focus on immediate kernel updates that contain the reverted commits and proper command cleanup procedures. System administrators should prioritize applying the patched kernel versions that address both the original chip reset handling issues and the race condition in DMA unmap operations. Organizations using QLogic Fibre Channel hardware should implement monitoring for unusual command queue behavior and establish automated alerting for memory usage patterns that might indicate command accumulation. The fix requires careful coordination of command state management during reset operations and proper synchronization mechanisms to prevent concurrent access to DMA mapping functions, aligning with common security practices for preventing race conditions in kernel-level code as outlined in various security frameworks and standards.