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A kernel object pointer validation flaw in ThreadX system calls allows attackers to supply pointers to reserved memory regions.

Moderate
mrybczyn published GHSA-wcfg-5jpf-hhxq Oct 14, 2025

Package

ThreadX (Eclipse ThreadX)

Affected versions

<= 6.4.2

Patched versions

6.4.3

Description

Summary

A kernel object pointer validation flaw in ThreadX system calls allows attackers to supply kernel pointers to reserved memory regions. This can cause the kernel to access invalid memory when reading the object’s type ID, resulting in a system exception and a denial-of-service (DoS) condition.

Details

In ThreadX, many system calls that accept kernel object pointers only check whether the pointer is outside the module memory region. However, they do not verify whether the pointer actually points to a valid kernel object or whether it falls within reserved or otherwise unmapped memory regions.

Specifically, ThreadX uses macros such as TXM_MODULE_MANAGER_PARAM_CHECK_OBJECT_FOR_USE to validate kernel object pointers passed to system calls. The relevant code is as follows:

threadx/common_modules/module_manager/inc/txm_module_manager_util.h

/* Kernel objects should be outside the module at the very least.  */
#define TXM_MODULE_MANAGER_PARAM_CHECK_OBJECT_FOR_USE(module_instance, obj_ptr, obj_size) \
    (TXM_MODULE_MANAGER_ENSURE_OUTSIDE_MODULE(module_instance, obj_ptr, obj_size) || \
     (_txm_module_manager_created_object_check(module_instance, (void *)obj_ptr) == TX_FALSE) || \
     ((void *) (obj_ptr) == TX_NULL))


/* When creating an object, the object must be inside the object pool.  */
#define TXM_MODULE_MANAGER_PARAM_CHECK_OBJECT_FOR_CREATION(module_instance, obj_ptr, obj_size) \
    ((TXM_MODULE_MANAGER_ENSURE_INSIDE_OBJ_POOL(module_instance, obj_ptr, obj_size) && \
      (_txm_module_manager_object_size_check(obj_ptr, obj_size) == TX_SUCCESS)) || \
     (_txm_module_manager_created_object_check(module_instance, (void *)obj_ptr) == TX_FALSE) || \
     ((void *) (obj_ptr) == TX_NULL))

This macro checks that:

  • The object pointer is outside the module's memory region (TXM_MODULE_MANAGER_ENSURE_OUTSIDE_MODULE), but does not ensure the pointer is within a valid, mapped, and accessible kernel memory region.

  • The object is not already a created object (_txm_module_manager_created_object_check).

  • The pointer is not NULL.

However, there is no check to ensure that obj_ptr does not point to reserved or unmapped memory. As a result, a pointer that is outside the module region but within a reserved or invalid area will pass this check, and the kernel will later dereference it, potentially causing a system exception.

As a result, an attacker can craft a system call with a pointer that lies outside the module region but within a reserved or unmapped area of the address space. When the kernel attempts to read the type ID or other fields from this pointer, it triggers an invalid memory access (e.g., a HardFault or BusFault on ARM Cortex-M), causing the system to crash.

Impact

  • Type: Denial of Service (DoS)

  • Who is impacted: Any system running ThreadX where untrusted code (such as user modules or external inputs) can supply kernel object pointers to system calls.

  • Severity: An attacker can crash the entire system by passing a pointer to reserved memory, causing persistent denial of service until a reboot.

Affected Syscalls

The affected syscalls are as follows:

timer_info_get,timer_delete,timer_deactivate,timer_create,timer_change,timer_activate,thread_wait_abort,thread_time_slice_change,thread_terminate,thread_suspend,thread_resume,thread_reset,thread_relinquish,thread_priority_change,thread_preemption_change,thread_info_get,thread_entry_exit_notify,thread_delete,thread_create,semaphore_put_notify,semaphore_put,semaphore_prioritize,semaphore_info_get,semaphore_get,semaphore_delete,semaphore_create,semaphore_ceiling_put,queue_send_notify,queue_send,queue_receive,queue_prioritize,queue_info_get,queue_front_send,queue_flush,queue_delete,queue_create,mutex_put,mutex_prioritize,mutex_info_get,mutex_get,mutex_delete,mutex_create,event_flags_set_notify,event_flags_set,event_flags_info_get,event_flags_get,event_flags_delete,event_flags_create,byte_release,byte_pool_prioritize,byte_pool_info_get,byte_pool_delete,byte_pool_create,byte_allocate,block_release,block_pool_prioritize,block_pool_info_get,block_pool_delete,block_pool_create,block_allocate

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Local
Attack Complexity Low
Attack Requirements Present
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality None
Integrity None
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVE ID

CVE-2025-55078

Weaknesses

Improper Handling of Parameters

The product does not properly handle when the expected number of parameters, fields, or arguments is not provided in input, or if those parameters are undefined. Learn more on MITRE.

Credits