SSL/TLS Version Security
Older SSL and early TLS protocol versions have known vulnerabilities and should not be used; only TLS 1.2 and 1.3 are considered secure for protecting sensitive connections today.
Also known as: TLS 1.3, TLS security, SSL deprecation
Last reviewed: 10 June 2026
SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are the protocols that encrypt internet connections. Over decades of use, earlier versions accumulated critical vulnerabilities: SSL 3.0 is vulnerable to the POODLE attack, TLS 1.0 and 1.1 to BEAST and related attacks. These protocols should not be used for sensitive communications and modern browsers and servers disable them.
TLS 1.2 remains in widespread use and is considered acceptable with careful cipher configuration. TLS 1.3, released in 2018, offers improved security and performance through a simplified handshake and removal of legacy cryptographic options. When a browser warns that a connection uses an outdated security protocol, proceeding risks exposing credentials and data to interception.
For consumers, the practical implication is to keep browsers and operating systems updated, which automatically brings current TLS support, and to treat protocol-version security warnings seriously. For website owners and organisations, disabling TLS 1.0/1.1 on servers is a baseline compliance requirement for PCI DSS and many other security frameworks.