RFC 9292, "Binary Representation of HTTP Messages", August 2022

Errata ID: 8559
Status: Reported
Type: Technical
Publication Format(s) : TEXT, PDF, HTML
Reported By: Ricardo Perez
Date Reported: 2025-08-29

Section 3.6 says:

invalid messages.  A recipient MUST treat a message that contains
field values that would cause an HTTP/2 message to be malformed
according to Section 8.2.1 of [HTTP/2] as invalid; see Section 4.

It should say:

invalid messages.  A recipient MUST treat a message that contains
field names and values that would cause an HTTP/2 message to be
malformed according to Section 8.2.1 of [HTTP/2] as invalid; see
Section 4.

Notes:

Calling out field name handling explicitly since encoding and decoding entities might be using different versions of HTTP.

An additional section explaining encoder and decoder expectations might be useful as well, something like the following: "To ensure interoperability where communicating entities use different HTTP versions, encoders MUST convert field names to lowercase upon encoding. Decoders MUST treat any uppercase field names as an error."

Report New Errata