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www.rfc-editor.org • October 15, 2026

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). ¶

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 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 . ¶

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. ¶

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 algorithms that will be "safe" once quantum computers are feasible [ PQC ] . Initial discussions in the IETF community happened around the same time [ CFRGSLIDES ] . ¶

In 2024, NIST released standards for [ ML-KEM ] , [ ML-DSA ] , and [ SLH-DSA ] . Many other countries and organizations are publishing their roadmaps, including the multi-national standards organization ETSI [ ETSI ] . ¶

While the industry was waiting for NIST to finish standardization, the IETF has had several efforts underway. A working group was formed in early 2023 to work on the use of Post-Quantum Cryptography (PQC) in IETF protocols [ PQUIPWG ] . Several other working groups, including TLS [ TLSWG ] , are working on specifications to support hybrid algorithms and identifiers, for use during a transition from classic to a post-quantum world. ¶

It is important to note that effort within the TLS Working Group is focused exclusively on TLS 1.3 or later. Put bluntly, PQC for TLS 1.2 will not be specified (see Section 4 ) at any time; anyone wishing to deploy PQC should expect to use TLS 1.3. ¶

3. Security Considerations

This entire document is security and provides post-quantum security concerns as an additional reason to upgrade to TLS 1.3. ¶

4. IANA Considerations

No TLS registries [ TLS13REG ] are being closed by this document. Rather, this document modifies the instructions to IANA and the TLS Designated Experts to constrain the type of entries that can be added to existing registries. ¶

This document does not introduce any new limitations on the registrations for either of the following two registries: ¶

TLS Application- Layer Protocol Negotiation (ALPN) Protocol IDs ¶

TLS Exporter Labels ¶

The following note has been added to the other TLS registries: ¶

Any TLS entry added after the IESG approves publication of RFC 9851 is intended for TLS 1.3 or later, and makes no similar requirement on DTLS. Such entries should have an informal indication like "For TLS 1.3 or later" in that entry, such as the " " column. ¶

At the time of publication, the note has been added to the following TLS registries: ¶

TLS Authorization Data Formats ¶

TLS Cached Information Type Values ¶

TLS Certificate Compression Algorithm IDs ¶

TLS Certificate Status Types ¶

TLS Certificate Types ¶

TLS Client Certificate Type Identifiers ¶

TLS EC Point Formats ¶

TLS ExtensionType Values ¶

TLS Heartbeat Message Types ¶

TLS Heartbeat Modes ¶

TLS KDF Identifiers ¶

TLS Psk Key Exchange Mode ¶

TLS Signature Algorithm ¶

TLS Signature Scheme ¶

TLS Supplemental Data Formats (Supplemental Data Type) ¶

TLS Supported Groups ¶

TLS User Mapping Type Values ¶

Any TLS registry created after this document is approved for publication should indicate whether the actions defined here are applicable. ¶

5.1. Normative References

5.2. Informative References

We gratefully acknowledge Amanda Baber , David Dong , and Sabrina Tanamal of IANA for their help in revising and clarifying Section 4 . ¶

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

IETF Publishes RFCs on Post-Quantum Cryptography and TLS 1.3 Standards On October 15, 2026, the IETF published RFC 9794, defining terminology for hybrid cryptographic schemes that combine post-quantum and traditional asymmetric algorithms. This document aims to provide clarity and consistency across various protocols and organizations. Additionally, RFC 9851 was released, indicating that TLS 1.2 will receive no changes except for urgent security fixes, while the use of TLS 1.3 continues to grow. These documents are informational and do not constitute Internet Standards. They represent the consensus of the IETF community and have been approved by the Internet Engineering Steering Group (IESG). No specific vulnerabilities or active threats were reported in relation to these documents. 3

Extracted Entities

Platforms (4)

ALPN DTLS TLS 1.2 TLS 1.3