CVE-2026-80690 in Linux
Summary
by MITRE • 08/28/2026
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Initialize hba->rpmbs list in ufshcd
Initialize the hba->rpmbs list in ufshcd_alloc_host() to prevent NULL pointer dereference in the device teardown path if ufs_rpmb_probe() fails.
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Analysis
by VulDB Data Team • 08/28/2026
The Linux kernel's Universal Flash Storage (UFS) subsystem contains a critical initialization flaw within its Host Bus Adapter management logic, specifically affecting the Reliable Partition Memory Block Store RPMBS functionality. This vulnerability arises from an incomplete setup sequence during the host controller allocation phase. When the ufshcd_alloc_host function is invoked to initialize the HBA structure, it fails to properly initialize the hba->rpmbs list before proceeding with subsequent probe operations. The rpmbs feature allows for secure storage of cryptographic keys and other sensitive data within the UFS device itself, relying on a linked list structure managed by the kernel driver to track active instances or configurations. By neglecting this initialization step, the pointer remains in an undefined state rather than being set to NULL or properly allocated as an empty list head.
This oversight creates a direct path for a null pointer dereference vulnerability during the device teardown process. If the ufs_rpmb_probe function encounters any error condition and returns failure, the kernel's cleanup routines are triggered to release resources associated with the host adapter. These cleanup paths assume that all structures within the HBA have been correctly initialized by ufshcd_alloc_host. Because the rpmbs list was not zeroed out or linked properly at allocation time, attempting to traverse or free this uninitialized list results in accessing invalid memory addresses. In a local context, such as when a user triggers device removal or system shutdown with an affected UFS storage component present, this can lead to a kernel panic and subsequent system crash, effectively causing a denial of service against the host machine.
From a technical classification perspective, this issue aligns closely with CWE-252, which describes unchecked return values leading to improper resource management, as well as CWE-476 regarding NULL pointer dereferences in C/C++ code where expected initialization steps are omitted. The operational impact is primarily confined to system stability and availability rather than direct privilege escalation or data exfiltration at the point of exploitation. However, a kernel panic can disrupt critical services running on the host, leading to significant downtime. Furthermore, if this vulnerability were part of a larger attack chain involving other memory corruption flaws, it could potentially be leveraged for more severe outcomes, although in its current isolated form, it serves primarily as an availability risk.
Mitigation strategies focus heavily on applying vendor-provided kernel patches that correct the initialization sequence within ufshcd_alloc_host. System administrators should ensure their Linux distributions are updated with the latest stable kernels where this fix has been merged upstream. For environments running custom or older kernel versions, backporting the specific commit that initializes hba->rpmbs before any probe operations is essential. Additionally, developers integrating UFS drivers into embedded systems must rigorously test error paths during device initialization to ensure that all allocated structures are properly cleaned up regardless of whether probing succeeds or fails, thereby preventing similar resource management errors in related subsystems.