CVE-2026-0648 in ThreadX
Summary
by MITRE • 01/27/2026
The vulnerability stems from an incorrect error-checking logic in the CreateCounter() function (in threadx/utility/rtos_compatibility_layers/OSEK/tx_osek.c) when handling the return value of osek_get_counter(). Specifically, the current code checks if cntr_id equals 0u to determine failure, but @osek_get_counter() actually returns E_OS_SYS_STACK (defined as 12U) when it fails. This mismatch causes the error branch to never execute even when the counter pool is exhausted.
As a result, when the counter pool is depleted, the code proceeds to cast the error code (12U) to a pointer (OSEK_COUNTER *), creating a wild pointer. Subsequent writes to members of this pointer lead to writes to illegal memory addresses (e.g., 0x0000000C), which can trigger immediate HardFaults or silent memory corruption.
This vulnerability poses significant risks, including potential denial-of-service attacks (via repeated calls to exhaust the counter pool) and unauthorized memory access.
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Analysis
by VulDB Data Team • 01/27/2026
The vulnerability described in CVE-2026-0648 represents a critical software flaw within the ThreadX real-time operating system's OSEK compatibility layer, specifically affecting the CreateCounter() function implementation in tx_osek.c. This issue manifests as a fundamental logic error in error handling that stems from a mismatch between expected and actual return values from the osek_get_counter() system call. The flaw demonstrates poor defensive programming practices and highlights the importance of proper error validation in embedded systems where resource exhaustion can lead to catastrophic system failures.
The technical implementation of this vulnerability occurs due to incorrect conditional logic that evaluates cntr_id == 0u as the failure indicator for osek_get_counter() calls, when in reality the function returns E_OS_SYS_STACK with a value of 12U upon failure conditions. This fundamental mismatch between expected and actual error codes creates a scenario where the error handling branch is never properly executed, allowing the system to continue processing with invalid return values. The error code 12U is subsequently cast directly to a pointer type OSEK_COUNTER *, creating what is known as a wild pointer condition that points to an invalid memory address. This casting operation transforms a system error code into a memory reference, effectively bypassing normal error recovery mechanisms.
The operational impact of this vulnerability extends beyond simple system instability, presenting serious security implications that align with ATT&CK technique T1499.100 for endpoint denial of service and potentially enabling privilege escalation through memory corruption. When the counter pool becomes exhausted, the system's continued execution with invalid pointers leads to immediate HardFault exceptions or silent memory corruption that can compromise system integrity. The vulnerability is particularly dangerous because it can be triggered through repeated calls to CreateCounter() that systematically exhaust the available counter resources, creating a reliable denial-of-service attack vector that can render the embedded system non-functional. This behavior directly violates CWE-252, which addresses the lack of checks for error conditions, and CWE-121, which covers stack-based buffer overflow conditions that can occur when invalid pointers are dereferenced.
Mitigation strategies for this vulnerability require immediate implementation of proper error handling logic that correctly interprets the return values from osek_get_counter() and validates all pointer assignments before dereferencing. The fix should ensure that error codes are properly checked against their defined values rather than relying on arbitrary comparisons, and that invalid return values from system calls are handled gracefully without proceeding to pointer casting operations. Additionally, implementing proper resource management with bounds checking and overflow protection mechanisms would prevent the counter pool exhaustion scenario that triggers this vulnerability, while also providing appropriate error reporting to prevent silent failures that could lead to system instability or security compromise.