CVE-2026-17577 SSL Zen <= 4.7.42 - Reflected Cross-Site Scripting via 'uri' Parameter

Q: What is CVE-2026-17577?

CVE-2026-17577 is a medium-severity cross-site scripting vulnerability in sslzen SSL Zen — SSL Certificate Installer & HTTPS Redirects, published on 25 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Q: Is CVE-2026-17577 being exploited?

There is no known exploitation of CVE-2026-17577 in the wild and no public exploit code.

Q: How do I fix CVE-2026-17577?

No fix has been published for CVE-2026-17577 yet. Limit exposure of the affected software until one is available.

Medium 6.1 Published 25 Sep 2026 Updated 25 Sep 2026

Unauthenticated attackers can inject arbitrary web scripts via the 'uri' parameter in the SSL Zen WordPress plugin, potentially executing code in victim browsers.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-17577?

CVE-2026-17577 is a medium-severity cross-site scripting vulnerability in sslzen SSL Zen — SSL Certificate Installer & HTTPS Redirects, published on 25 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

The SSL Zen plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'uri' (and 'host') parameters in versions up to, and including, 4.7.42. The ssl_zen_messages::getMessages() function builds the 'token_missmatch' message using base64_decode(sanitize_text_field($_REQUEST['uri'])) and (optionally) base64_decode(sanitize_text_field($_REQUEST['host'])). sanitize_text_field() cannot strip HTML/JavaScript that is hidden inside a base64-encoded blob, and the resulting decoded raw HTML is echoed unescaped by showMessage() . This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a specially crafted link.

Weakness: CWE-79

Which versions are affected by CVE-2026-17577?

How do I fix CVE-2026-17577?

No fix has been published for CVE-2026-17577 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-17577 being exploited?