Cloudanix VulnDB

CVE-2026-45118

Critical · 9.3

CVSS

9.3

EPSS

0.5%

Published

Aug 18, 2026

CISA due date

—

The record

MyBB is free and open source forum software. Prior to 1.8.40, the Contact module does not validate a redirect URL or protocol correctly, resulting in an open redirect and reflected JavaScript code injection. contact.php accepts the redirect target from the from HTTP parameter in $mybb->input['from'] or the Referer HTTP header in $_SERVER['HTTP_REFERER'] and passes it to redirect() without sufficient verification. A javascript: URI becomes the target of the `Click here if you don't want to wait any longer` link because $force_redirect is true, allowing script execution when a victim selects the link. This issue is fixed in version 1.8.40.

Affected packages

Ecosystem Package Introduced Fixed

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