When NetX Secure is built with NX_SECURE_KEY_CLEAR, every TLS record sent on an active session is wiped after it has been handed to TCP. By then the TCP layer owns the packet chain and may already have released it to the packet pool. The wipe therefore writes zeros into packets that are free or in use by another thread, and when a reused packets pointers no longer describe the old data, the length of the wipe underflows and it runs past the end of the packet pool.
Weakness
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.