Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the “signature_algorithms_cert” TLS extension. The crash occurs if an invalid or unrecognized signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack.
Denial of Service
OpenSSL 1.1.1 users should upgrade to 1.1.1g