How to fix hsts max age too short on WordPress.org

Steps for WordPress.org

1. WordPress core does not set HSTS — you must set it at the server or plugin level.
2. Plugin method: Install 'Headers Security Advanced & HSTS WP' or 'HTTP Headers' from Plugins → Add New. Activate and navigate to the plugin's settings page. Enable Strict-Transport-Security and set max-age to 31536000 with includeSubDomains checked.
3. Apache method: In your root .htaccess, inside a <IfModule mod_headers.c> block add: Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
4. Nginx method: In your server {} block for port 443: add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always; — reload Nginx after saving.
5. Verify at securityheaders.com.

What is hsts max age too short?

HTTP Strict Transport Security (HSTS) is a security header your web server sends to browsers that says: "Only ever connect to this site over HTTPS — never plain HTTP." The `max-age` value inside that header tells the browser how many seconds to remember and enforce that rule. A value of 86400 means just one day — after 24 hours the browser forgets the instruction and could allow an unencrypted HTTP connection again. The industry standard is 31536000 (one full year), meaning the browser stays protected for 365 days after each visit.

A short max-age creates a real window of vulnerability every single day. If a visitor's browser cache expires and they visit your store over an insecure network (coffee shop Wi-Fi, hotel hotspot), an attacker can intercept that initial unencrypted HTTP request and steal login credentials, session cookies, or payment data — a classic SSL-stripping attack. Beyond security, Google has used HTTPS as a ranking signal since 2014 and continues to favor sites that implement it properly; a misconfigured HSTS header signals to security-aware crawlers and auditors that your HTTPS setup is incomplete. Short max-age values are also explicitly flagged by OWASP and browser preload-list requirements, and many enterprise buyers and compliance frameworks (PCI-DSS, SOC 2) require HSTS to be set correctly before approving a vendor.

See the complete Hsts max age too short guide for every platform and the full background.