This flaw occurs when the NetX Duo function calculating a certificate signature’s length does not verify that the length field is non‑zero. A certificate containing an empty ASN.1 BIT STRING will therefore be parsed as having an astronomically large length, causing subsequent code to read or write past the end of the provided buffer. When such a certificate is received during an unverified TLS handshake, the result is a remote memory corruption that may lead to a crash or arbitrary code execution. The vulnerability is identified by its CWE numbers for out‑of‑bounds access and integer overflow.

The vulnerability affects the Eclipse Foundation’s NetX Duo real‑time operating system. No specific version range is cited in the advisory; all releases of NetX Duo that have not applied the referenced correction are potentially impacted.

The CVSS score of 8.7 indicates high severity, and the lack of EPSS or KEV inclusion does not diminish the risk of exploitation. Since the input is supplied by a remote peer during the TLS handshake, an attacker can craft a malicious certificate and initiate a connection to trigger the flaw. The attack does not require prior authentication and therefore can be performed against any device or system that accepts TLS client certificates using NetX Duo.