CVE-2021-3449

A flaw was found in openssl. A server crash and denial of service attack could occur if a client sends a TLSv1.2 renegotiation ClientHello and omits the signature_algorithms extension but includes a signature_algorithms_cert extension. The highest threat from this vulnerability is to system availability.

This flaw only affects OpenSSL 1.1.1, older versions are not affected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

This flaw can be mitigated by disabling TLS renegotiation on servers compiled with OpenSSL. It is enabled by default, but can be disabled for servers which do not require it and can be used to mitigate this flaw. Versions of httpd package shipped with Red Hat Enterprise Linux 8 have TLS renegotiation disabled by default.