CVE-2023-53238 in Linux
Summary
by MITRE • 09/15/2025
In the Linux kernel, the following vulnerability has been resolved:
phy: hisilicon: Fix an out of bounds check in hisi_inno_phy_probe()
The size of array 'priv->ports[]' is INNO_PHY_PORT_NUM.
In the for loop, 'i' is used as the index for array 'priv->ports[]'
with a check (i > INNO_PHY_PORT_NUM) which indicates that INNO_PHY_PORT_NUM is allowed value for 'i' in the same loop.
This > comparison needs to be changed to >=, otherwise it potentially leads to an out of bounds write on the next iteration through the loop
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Analysis
by VulDB Data Team • 01/11/2026
The vulnerability identified as CVE-2023-53238 resides within the Linux kernel's phy driver for hisilicon devices, specifically in the hisi_inno_phy_probe() function. This issue represents a classic buffer overread condition that could potentially escalate to arbitrary code execution or system instability. The flaw manifests in the boundary checking logic of a for loop that iterates through the phy ports array, where improper comparison operators create a window for memory corruption. The affected driver manages hardware phy controllers used in various networking and communication devices, making this vulnerability particularly concerning for embedded systems and server infrastructure that rely on hisilicon chipsets.
The technical root cause stems from an incorrect comparison operator within the loop validation logic. The array priv->ports[] has a defined size of INNO_PHY_PORT_NUM elements, yet the loop condition uses i > INNO_PHY_PORT_NUM instead of the correct i >= INNO_PHY_PORT_NUM. This subtle but critical error means that when the loop variable i reaches the value INNO_PHY_PORT_NUM, the condition evaluates to false, allowing the loop to continue and attempt accessing memory beyond the allocated array boundaries. This logical flaw creates an out of bounds write condition that can overwrite adjacent memory locations, potentially corrupting critical data structures or executing unintended code paths. The vulnerability aligns with CWE-129, which specifically addresses improper validation of array indices, and represents a common class of programming errors that can lead to memory corruption vulnerabilities.
The operational impact of this vulnerability extends across various Linux-based systems utilizing hisilicon phy controllers, particularly those in networking equipment, embedded devices, and server platforms. When exploited, the out of bounds write condition could result in system crashes, denial of service conditions, or more severe consequences if attackers can manipulate the memory corruption to achieve code execution. The vulnerability is especially dangerous in environments where the kernel driver is loaded automatically during system boot or when hot-plugging phy devices, as these scenarios increase the likelihood of triggering the flawed code path. Systems using the affected kernel versions may experience unexpected behavior, system instability, or complete system failure depending on the memory corruption patterns and the specific implementation details of the affected hardware platforms.
Mitigation strategies for CVE-2023-53238 should prioritize immediate kernel updates from the vendor, as the fix involves correcting the comparison operator from > to >= in the loop validation logic. Organizations should also implement comprehensive monitoring for system stability issues or unexpected reboots that could indicate exploitation attempts. The fix addresses the vulnerability at its source by ensuring proper boundary validation, preventing the loop from executing beyond the allocated array limits. Security teams should also consider implementing runtime protections such as stack canaries, address space layout randomization, and kernel memory protection mechanisms to reduce the potential impact of similar vulnerabilities. Additionally, maintaining up-to-date security patches and following the principle of least privilege for kernel module loading can help minimize the attack surface. This vulnerability demonstrates the critical importance of thorough code review processes and automated testing for memory safety conditions, particularly in kernel space code where errors can have far-reaching consequences across entire computing platforms.