advisory-db/crates/openssl-src/RUSTSEC-2021-0055.md

[advisory]
id = "RUSTSEC-2021-0055"
package = "openssl-src"
aliases = ["CVE-2021-3449"]
categories = ["denial-of-service"]
date = "2021-05-01"
url = "https://www.openssl.org/news/secadv/20210325.txt"

[versions]
patched = [">= 111.15"]

NULL pointer deref in signature_algorithms processing

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 clients are not impacted by this issue.