In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer overflow inside the DecodedCert structure in GetName in wolfcrypt/src/asn.c because the domain name location index is mishandled. Because a pointer is overwritten, there is an invalid free.

In wolfSSL through 4.1.0, there is a missing sanity check of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer over-read in CheckCertSignatureex in wolfcrypt/src/asn.c.

wolfSSL 4.1.0 has a one-byte heap-based buffer over-read in DecodeCertExtensions in wolfcrypt/src/asn.c because reading the ASNBOOLEAN byte is mishandled for a crafted DER certificate in GetLengthex.