A NULL-pointer dereference has been found in OpenSSL versions 1.1.1d, 1.1.1e and 1.1.1f. 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.
A NULL-pointer dereference has been found in OpenSSL versions 1.1.1d, 1.1.1e and 1.1.1f. 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.
https://www.openssl.org/news/secadv/20200421.txt https://github.com/openssl/openssl/commit/eb563247aef3e83dda7679c43f9649270462e5b1
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