CVE-2026-93046 in Linux
Summary
by MITRE • 09/17/2026
In the Linux kernel, the following vulnerability has been resolved:
software node: Fix software_node_get_reference_args() with index -1
The bounds check for the index passed to software_node_get_reference_args() was failing when passed UINT_MAX, this in turn would lead to an out of bound access in the property array. Fix the bound check to also cover the UINT_MAX case.
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Analysis
by VulDB Data Team • 09/18/2026
A critical integer overflow vulnerability has been identified within the Linux kernel's device tree handling subsystem, specifically affecting the software_node_get_reference_args function. This flaw stems from a defective bounds checking mechanism that fails to properly validate index values when they are passed as unsigned integers with maximum possible magnitude. In C programming and low-level system development, it is common for developers to use signed integer types like int or long for array indexing because these types naturally handle negative indices through two's complement representation. However, the software_node_get_reference_args function accepts an index parameter that can be interpreted in multiple ways depending on how the caller passes data. When a caller intends to pass a negative one value indicating no specific argument should be selected, but instead provides UINT_MAX due to implicit type conversion or explicit unsigned casting, the existing validation logic does not recognize this as a valid error condition. Instead of rejecting the input, the function proceeds with array access operations using this excessively large index value.
The technical root cause lies in the comparison logic used during the bounds check phase. The original implementation likely compared the incoming index against the total number of available properties without accounting for the wrap-around behavior inherent to unsigned integer arithmetic. Since UINT_MAX represents the highest possible value for a 32-bit or 64-bit unsigned integer, subtracting one from it results in zero only if proper signed conversion occurs before comparison. Without explicit casting to a signed type prior evaluation, the index remains at its maximum positive value. Consequently, when this unchecked value is used as an offset into the property array, it triggers an out-of-bounds memory access. This scenario exemplifies CWE-190 Integer Overflow or Wraparound combined with CWE-787 Out-of-Bounds Write Read depending on subsequent operations performed after retrieving the reference arguments.
From a security perspective, this vulnerability poses significant risks to system stability and potential remote code execution scenarios if exploitable in certain contexts. An attacker who can influence the input parameters passed to software_node_get_reference_args might leverage this flaw to read sensitive kernel memory contents or overwrite adjacent data structures within the kernel space. Such unauthorized access could lead to privilege escalation, denial of service through kernel panic caused by corrupted memory states, or further exploitation chains involving other vulnerabilities in nearby subsystems. The impact is particularly severe because device tree parsing often occurs during early boot processes where security controls may not yet be fully initialized and monitoring mechanisms are less effective at detecting anomalous behavior patterns typical of exploit attempts.
Mitigation strategies primarily involve applying the upstream kernel patch that corrects the bounds checking logic to explicitly handle UINT_MAX cases by converting indices to signed types before performing comparisons against array limits. System administrators should ensure their systems run patched versions of the Linux kernel where this fix has been integrated into stable releases. Additionally, developers integrating software node functionalities must review all call sites for software_node_get_reference_args to verify that index parameters are correctly typed and validated before invocation. Implementing static analysis tools configured to detect potential integer overflows in C codebases can help prevent similar issues during future development cycles. Regular security audits focusing on device tree handling components will also reduce exposure to such vulnerabilities by ensuring consistent adherence to safe coding practices aligned with industry standards like CWE guidelines for input validation and memory safety principles outlined in ATT&CK techniques related to privilege escalation via kernel exploitation vectors.