CVE-2026-23202 in Linux
Summary
by MITRE • 02/14/2026
In the Linux kernel, the following vulnerability has been resolved:
spi: tegra210-quad: Protect curr_xfer in tegra_qspi_combined_seq_xfer
The curr_xfer field is read by the IRQ handler without holding the lock to check if a transfer is in progress. When clearing curr_xfer in the combined sequence transfer loop, protect it with the spinlock to prevent a race with the interrupt handler.
Protect the curr_xfer clearing at the exit path of tegra_qspi_combined_seq_xfer() with the spinlock to prevent a race with the interrupt handler that reads this field.
Without this protection, the IRQ handler could read a partially updated curr_xfer value, leading to NULL pointer dereference or use-after-free.
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Analysis
by VulDB Data Team • 05/24/2026
The vulnerability described in CVE-2026-23202 resides within the Linux kernel's SPI subsystem, specifically affecting the Tegra210 Quad SPI controller driver. This issue represents a classic race condition scenario that can lead to critical system instability and potential security implications. The vulnerability manifests in the tegra_qspi_combined_seq_xfer function where the curr_xfer field is manipulated without proper synchronization mechanisms, creating a scenario where concurrent access by different execution contexts can result in unpredictable behavior.
The technical flaw occurs due to improper locking mechanisms around the curr_xfer field access within the Tegra SPI driver implementation. The curr_xfer field serves as a critical indicator of ongoing SPI transfer operations and is accessed by both the main transfer function and the interrupt handler. When the interrupt handler reads this field without holding the appropriate spinlock, it creates a window where the field might contain inconsistent or partially updated values. This particular race condition is classified under CWE-362, which deals with concurrent execution using shared data structures without proper synchronization. The vulnerability specifically impacts the interrupt handler's ability to accurately determine the state of ongoing transfers, as the field can be modified by the main transfer loop while the interrupt handler is attempting to read it.
The operational impact of this vulnerability extends beyond simple functional failures to potentially compromise system stability and security. When the race condition occurs, the interrupt handler may read a partially updated curr_xfer value, which could result in either a NULL pointer dereference or a use-after-free condition. These outcomes can lead to kernel panics, system crashes, or in more severe scenarios, allow for privilege escalation attacks. The use of spinlocks in this context aligns with the ATT&CK framework's concept of privilege escalation through kernel-level vulnerabilities, where attackers can exploit such race conditions to gain elevated system privileges. The vulnerability affects systems utilizing Tegra210-based hardware platforms that rely on the quad SPI controller for communication with peripheral devices, potentially impacting embedded systems, automotive platforms, and mobile devices.
The mitigation strategy for this vulnerability requires implementing proper spinlock protection around the curr_xfer field modification operations within the tegra_qspi_combined_seq_xfer function. This approach ensures that when the field is cleared or modified during the transfer loop exit path, the interrupt handler cannot concurrently access it with inconsistent data. The fix aligns with standard kernel development practices for concurrent programming and follows the principle of protecting shared data structures through appropriate locking mechanisms. System administrators should prioritize applying the kernel patches that implement this spinlock protection, particularly in environments where system stability and security are paramount. The solution directly addresses the root cause by ensuring atomic access to the shared variable, preventing the race condition that could lead to system crashes or exploitable conditions. This vulnerability serves as a reminder of the critical importance of proper synchronization in kernel-level code and demonstrates how seemingly minor concurrency issues can result in significant system reliability and security implications.