CVE-2020-1967

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 unrecognised signature algorithm is received from the peer. This could
be exploited by a malicious peer in a Denial of Service attack. OpenSSL
version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue
did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g
(Affected 1.1.1d-1.1.1f).

Notes