CVE-2026-72088 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
scsi: hpsa: Fix DMA mapping leak on IOACCEL2 reset path
If phys_disk->in_reset is set, the function returns directly without undoing the resources acquired for the command. Add the missing error cleanup by unmapping the IOACCEL2 SG chain block when needed, unmapping the SCSI command, and dropping the outstanding IOACCEL command count before returning.
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Analysis
by VulDB Data Team • 08/16/2026
The Linux kernel vulnerability identified in the hpsa driver addresses a critical resource management flaw within the DMA mapping subsystem during specific hardware reset operations involving the IO Accelerator 2 controller. This issue manifests when the physical disk associated with an I/O request is flagged as being in a reset state, indicated by the phys_disk->in_reset variable being set to true. Under normal operational conditions, drivers must ensure that all resources acquired for processing a command are properly released regardless of whether the operation succeeds or fails. However, in this specific code path, the function prematurely returns upon detecting the reset condition without executing the necessary cleanup routines. This oversight results in a persistent leak of DMA mappings and associated kernel memory structures, which can degrade system stability over time as these unreleased resources accumulate.
From a technical perspective, the flaw resides in the error handling logic for commands directed at IOACCEL2 devices. When an I/O request is initiated, the driver allocates scatter-gather list blocks and maps them to physical addresses via DMA mapping functions to allow direct memory access by the hardware controller. If the device enters a reset state while these mappings are active but before they can be properly unmapped and freed, the kernel retains references to this memory without releasing it back to the pool. The fix introduces explicit cleanup steps that unmap the IOACCEL2 scatter-gather chain block, release the SCSI command structure, and decrement the counter tracking outstanding IOACCEL commands. This ensures that the internal state of the driver remains consistent with the actual resource usage, preventing the gradual exhaustion of DMA address space or kernel memory pools which could otherwise lead to system-wide performance degradation or allocation failures for subsequent I/O operations.
The operational impact of this vulnerability is primarily related to long-term reliability and potential denial-of-service conditions through resource exhaustion. While a single instance of this leak may have negligible immediate effects, repeated occurrences during frequent device resets or failover events can accumulate significant memory overhead. In high-availability environments where storage controllers undergo regular health checks or automatic reset procedures due to transient errors, this bug could progressively consume available DMA mapping resources. This depletion might eventually cause new I/O requests to fail with allocation errors, leading to application timeouts, data transfer interruptions, or in severe cases, kernel panics if the memory pressure becomes critical enough to impact other subsystems. The vulnerability is classified under CWE-401, which describes a missing release of memory after effective usage, highlighting the failure to properly deallocate resources that were successfully acquired during command processing.
To mitigate this risk and maintain system integrity, it is essential to apply the upstream kernel patch that resolves this issue in the hpsa driver. System administrators should ensure their Linux distributions are updated with the latest stable kernels containing this fix. For environments running custom or older kernel versions where immediate updates are not feasible, monitoring DMA mapping usage via tools like /proc/slabinfo can help detect abnormal growth patterns indicative of such leaks. Additionally, reviewing driver code for similar patterns in other storage controllers is advisable to prevent analogous resource management flaws. The remediation aligns with best practices defined by the MITRE ATT&CK framework under techniques related to resource exhaustion, emphasizing that proper lifecycle management of kernel resources is critical for maintaining the availability and resilience of enterprise infrastructure against both accidental degradation and potential exploitation vectors aimed at destabilizing systems through memory pressure.