RFC 9851: TLS 1.2 is in Feature Freeze

RFC 9851 TLS 1.2 Frozen July 2026 Salz & Aviram Standards Track [Page] Stream: Internet Engineering Task Force (IETF) RFC: 9851 Category: Standards Track Published: July 2026 ISSN: 2070-1721 Authors: R. Salz Akamai Technologies N. Aviram RFC 9851 TLS 1.2 is in Feature Freeze Abstract Use of TLS 1.3, which fixes some known deficiencies in TLS 1.2, is growing. This document specifies that no changes will be approved for TLS 1.2 outside of urgent security fixes (as determined by TLS Working Group consensus), new TLS Exporter Labels, and new Application-Layer Protocol Negotiation (ALPN) Protocol IDs. This applies to TLS only; it does not apply to DTLS (in any DTLS version).¶ Status of This Memo This is an Internet Standards Track document.¶ This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶ Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9851.¶ Copyright Notice Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved.¶ This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶ ▲ Table of Contents 1.  Introduction 2.  Implications for Post-Quantum Cryptography (PQC) 3.  Security Considerations 4.  IANA Considerations 5.  References 5.1.  Normative References 5.2.  Informative References Acknowledgments Authors' Addresses 1. Introduction TLS 1.3 [TLS13] fixes most known deficiencies with TLS 1.2 [TLS12] and its use is growing. Some examples of the fixes include encrypting more of the traffic so that it is not readable by outsiders and removing most cryptographic primitives that are now considered weak. Importantly, TLS 1.3 enjoys robust security proofs.¶ Both versions have several extension points. Items like new cryptographic algorithms, new supported groups (formerly "named curves"), etc., can be added without defining a new protocol. This document specifies that no changes will be approved for TLS 1.2 outside of urgent security fixes (as determined by TLS Working Group consensus) and the exceptions listed in Section 4.¶ This applies to TLS only. As such, it does not apply to DTLS, in any DTLS version.¶ 2. Implications for Post-Quantum Cryptography (PQC) Cryptographically relevant quantum computers, once available, are likely to greatly lessen the time and effort needed to break RSA, finite-field-based Diffie-Hellman (FFDH), or Elliptic Curve Cryptography (ECC) which are currently used in TLS. In 2016, the US National Institute of Standards and Technology (NIST) started a multi-year effort to standardize