The maintainers of OpenSSL have released a fix for two high-severity security flaws in its software that could be exploited to carry out denial-of-service (DoS) attacks and bypass certificate verification.
Tracked as CVE-2021-3449 and CVE-2021-3450, both the vulnerabilities have been resolved in an update (version OpenSSL 1.1.1k) released on Thursday. While CVE-2021-3449 affects all OpenSSL 1.1.1 versions, CVE-2021-3450 impacts OpenSSL versions 1.1.1h and newer.
OpenSSL is a software library consisting of cryptographic functions that implement the Transport Layer Security protocol with the goal of securing communications sent over a computer network.
According to an advisory published by OpenSSL, CVE-2021-3449 concerns a potential DoS vulnerability arising due to NULL pointer dereferencing that can cause an OpenSSL TLS server to crash if in the course of renegotiation the client transmits a malicious “ClientHello” message during the handshake between the server and a user. The issue was introduced as part of changes dating back to January 2018.
“If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello),…