CVE-2026-44974: @hapi/content header parser has a parameter smuggling issue that allows upload-filter bypass via duplicate parameters

The two parsers resolved duplicates inconsistently and silently:

• Content.disposition() retained the last occurrence of each parameter.
• Content.type() retained the first occurrence of charset and boundary.

Either behavior creates a parameter-smuggling primitive when another component in the request-processing chain (a WAF, reverse proxy, security filter, or alternate parser) resolves duplicates the opposite way. The primary attack vector is upload filename allowlist bypass:

Content-Disposition: form-data; name="file"; filename="safe.txt"; filename="shell.php"