The Python project announces a new release with several security fixes:
- CVE-2026-1299: gh-144125: BytesGenerator will now refuse to serialize (write) headers that are unsafely folded or delimited; see verify_generated_headers. (Contributed by Bas Bloemsaat and Petr Viktorin in gh-121650).
- gh-143935: Fixed a bug in the folding of comments when flattening an email message using a modern email policy. Comments consisting of a very long sequence of non-foldable characters could trigger a forced line wrap that omitted the required leading space on the continuation line, causing the remainder of the comment to be interpreted as a new header field. This enabled header injection with carefully crafted inputs.
- gh-143925: Reject control characters in data: URL media types.
- gh-143919: Reject control characters in http.cookies.Morsel fields and values.
- CVE-2026-0865: gh-143916: Reject C0 control characters within wsgiref.headers.Headers fields, values, and parameters.