Out-of-bounds read via an empty signature BIT STRING in NetX Secure X.509 parsing

In Eclipse ThreadX NetX Duo versions up to and including 6.5.2.202603, the NetX Secure X.509 parser accepts a certificate whose signature is an empty BIT STRING and records a signature length of 0xFFFFFFFF. A remote peer can present such a certificate during the TLS handshake, before authentication, and make the device read far outside the certificate buffer during signature verification, which is expected to fault.