CVE-2026-92478 in Linux
Summary
by MITRE • 09/17/2026
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Validate connected lane counts
The connected lane count is used by TX equalization code to index arrays sized by UFS_MAX_LANES. Reject zero and out-of-range RX or TX lane counts before they can be propagated.
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Analysis
by VulDB Data Team • 09/17/2026
This vulnerability addresses a critical input validation deficiency within the Universal Flash Storage core subsystem of the Linux kernel, specifically affecting the SCSI layer's handling of Ultra Fast Storage device configurations. The issue arises during the initialization phase where the system queries and processes the number of active data lanes for both transmit (TX) and receive (RX) paths on UFS devices. In standard operation, these lane counts are directly utilized by the TX equalization code to index into fixed-size arrays defined by the constant UFS_MAX_LANES. This architectural design assumes that all incoming lane count values will fall within a safe, predefined range corresponding to the maximum supported hardware capabilities. However, prior to this fix, the kernel failed to rigorously validate whether the reported lane counts were zero or exceeded the expected upper bounds before they were used as array indices.
The technical flaw lies in the absence of boundary checks for RX and TX lane count values retrieved from the connected UFS device. When a maliciously crafted or malfunctioning storage device reports an invalid number of lanes, such as zero or a value greater than UFS_MAX_LANES, the kernel proceeds to use these unvalidated integers as indices into internal data structures. This lack of sanitization creates a direct pathway for out-of-bounds memory access. If the reported count is larger than the array size, it results in an out-of-bounds read or write operation. Such memory corruption can lead to unpredictable system behavior, including kernel panics, data integrity violations, or potentially arbitrary code execution if the attacker can control the content written beyond the buffer boundaries through carefully crafted device responses during enumeration phases.
From a security perspective, this vulnerability is classified under CWE-125: Out-of-bounds Read and CWE-787: Out-of-bounds Write, depending on whether the equalization process reads from or writes to memory locations outside the allocated array limits. In terms of attack vectors, it aligns with ATT&CK technique T1046: Network Service Scanning if exploited during device discovery, though more accurately it represents a local privilege escalation vector via hardware interface manipulation (T1203: Exploitation for Privilege Escalation) when an attacker has physical access to the storage bus or can inject malformed UFS protocol frames. The operational impact is severe as it compromises kernel stability and security integrity. A successful exploit could allow a locally attached malicious device, such as a compromised SSD or SD card inserted into a vulnerable system, to crash the operating system causing denial of service, or potentially escalate privileges by corrupting kernel memory structures like function pointers or task descriptors.
To mitigate this risk, the primary remediation is applying the provided Linux kernel patch that enforces strict validation on connected lane counts before they are propagated to the TX equalization routines. Administrators should ensure their systems are updated with a kernel version containing this fix. Additionally, organizations relying on removable UFS storage in high-security environments should implement physical access controls and device whitelisting policies to prevent unauthorized or untrusted hardware from being connected to critical infrastructure. Monitoring for unusual system crashes during the enumeration of new storage devices can also serve as an indicator of attempted exploitation. Regular security audits focusing on input validation in kernel drivers, particularly those handling external hardware interfaces, are recommended to identify similar patterns where device-reported parameters are used without adequate bounds checking against internal array limits.