CVE-2021-3449 – NULL pointer deref in signature_algorithms processing

https://notcve.org/view.php?id=CVE-2021-3449

25 Mar 2021 — An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack. A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS c... • https://github.com/riptl/cve-2021-3449 • CWE-476: NULL Pointer Dereference •