SSH Tectia Client/Server/Connector 5.1.0 and earlier, Manager 2.2.0 and earlier, and other products, when using an RSA key with exponent 3, removes PKCS-1 padding before generating a hash, which allows remote attackers to forge a PKCS #1 v1.5 signature that is signed by that RSA key and prevents Tectia from correctly verifying X.509 and other certificates that use PKCS #1, a similar issue to CVE-2006-4339.