A vulnerability in node-forge before version 1.4.1 allows RSA PKCS#1 v1.5 signature forgery due to acceptance of non-canonical BER encodings of the DigestInfo during signature verification. This flaw affects verification of signatures using RSA keys with a low public exponent (e=3), enabling attackers to forge signatures without the private key. The issue is fixed in node-forge 1.4.1 by enforcing strict DER encoding checks on DigestInfo.