CVE-2026-95108: Deleting a user-mode module thread leaks its privileged kernel stack

One logical thread of a user-mode ThreadX module costs the Module Manager's shared object pool two allocations, not one. The module asks for a TXTHREAD control block through txmmoduleobjectallocate; txmmodulemanagerthreadcreate then takes a second allocation of TXMMODULEKERNELSTACKSIZE bytes for the privileged kernel stack that thread's system calls run on, and records it in the control block. Both come from txmmodulemanagerobjectpool and both are linked onto the module's allocation list.

The Module Manager's thread-delete dispatcher released only the first. The kernel stack stayed allocated until the whole module was stopped, so a module that creates, terminates and deletes threads in a loop — every state transition valid, every service returning TXSUCCESS — removed a fixed block from a finite pool shared by the manager and by every other loaded module, on every cycle, for as long as it stayed loaded. Once the pool is exhausted, no memory-protected module can create any kernel object and no user-mode module thread can be created anywhere in the system.

Vulnerable function: txmmodulemanagertxthreaddeletedispatch, in commonmodules/modulemanager/inc/txmmodulemanagerdispatch.h.