CVE-2026-23068 in Linux
Summary
by MITRE • 02/04/2026
In the Linux kernel, the following vulnerability has been resolved:
spi: spi-sprd-adi: Fix double free in probe error path
The driver currently uses spi_alloc_host() to allocate the controller but registers it using devm_spi_register_controller().
If devm_register_restart_handler() fails, the code jumps to the put_ctlr label and calls spi_controller_put(). However, since the controller was registered via a devm function, the device core will automatically call spi_controller_put() again when the probe fails. This results in a double-free of the spi_controller structure.
Fix this by switching to devm_spi_alloc_host() and removing the manual spi_controller_put() call.
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Analysis
by VulDB Data Team • 04/30/2026
This vulnerability exists in the Linux kernel's spi-sprd-adi driver where a double free condition occurs during the probe error path. The issue stems from improper resource management practices within the driver's initialization sequence, creating a critical memory corruption scenario that could be exploited by malicious actors. The vulnerability specifically affects the Spreadtrum ADI SPI driver which handles communication with various hardware components in embedded systems. When the driver encounters an error during probe execution, particularly when devm_register_restart_handler() fails, the code path leads to an improper cleanup sequence that results in the same memory structure being freed twice.
The technical flaw manifests from the inconsistent use of memory management functions within the driver's probe routine. The driver allocates the spi_controller structure using spi_alloc_host() which is a manual allocation function that requires explicit cleanup, but then registers the controller using devm_spi_register_controller() which is a device manager-based registration that automatically handles cleanup. This mismatch creates a scenario where the code explicitly calls spi_controller_put() at the error handling label put_ctlr, but the device manager core will automatically invoke spi_controller_put() again when the probe fails. The combination of these two cleanup operations results in a double free condition that corrupts kernel memory structures and potentially allows arbitrary code execution.
The operational impact of this vulnerability is severe as it can lead to system instability, kernel panics, and potential privilege escalation. Attackers could exploit this double free condition to corrupt kernel memory, potentially gaining unauthorized access to system resources or causing denial of service conditions. The vulnerability affects systems running Linux kernels that include the affected spi-sprd-adi driver, particularly those using Spreadtrum-based hardware platforms. The issue is classified as a memory safety vulnerability that aligns with CWE-415, which covers double free conditions in software. This type of vulnerability can be leveraged by attackers to execute arbitrary code with kernel privileges, making it a critical concern for embedded systems and mobile devices that rely on these drivers.
The fix for this vulnerability involves switching to a consistent memory management approach by replacing spi_alloc_host() with devm_spi_alloc_host() and removing the manual spi_controller_put() call from the error path. This ensures that the same device manager-based allocation and deallocation mechanism is used throughout the driver's lifecycle. The solution follows established best practices for device driver development in the Linux kernel and aligns with the ATT&CK framework's defense evasion techniques by preventing memory corruption exploits. This remediation approach ensures proper resource lifecycle management and prevents the double free condition from occurring. The fix demonstrates proper adherence to the Linux kernel's device management patterns and eliminates the potential for memory corruption that could be exploited by attackers to compromise system integrity. The resolution maintains the driver's functionality while ensuring memory safety through consistent use of device manager-based resource handling mechanisms.