Critical wolfSSL Vulnerability Allows ECDSA Signature Forgery and Certificate Bypass

A critical vulnerability in wolfSSL, a widely deployed SSL/TLS library targeting embedded and IoT systems, enables attackers to use forged certificates. The flaw stems from improper verification of the hash algorithm and its size during ECDSA signature checking, allowing signature forgery that undermines certificate validation.

wolfSSL is a common choice in resource-constrained environments — routers, IoT devices, automotive systems, and embedded firmware — where OpenSSL’s footprint is too large. A successful exploit enables man-in-the-middle attacks against devices relying on wolfSSL for TLS certificate validation.

Device manufacturers and OEMs embedding wolfSSL should apply vendor patches immediately. Security teams responsible for embedded systems should audit which products in their environment use wolfSSL and the version deployed, as firmware updates in IoT environments often lag considerably behind library releases.