NGINX SMTP upstream header injection (CVE-2026-28753)

Summary

Attacker-controlled DNS responses may inject SMTP upstream headers.

Vulnerability ID	Vulnerability Overview
CVE-2026-28753	The ngx_mail_smtp_module does not properly handle CRLF sequences in DNS responses. A malicious DNS server can inject headers into upstream SMTP requests and manipulate request content.

Affected Supported TeraStations

TS5020 / TS3030
- Fixed in firmware version 3.16
 

 

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Date	Description
10/14/2026	Initial release

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