CVE-2026-45118
MyBB is free and open source forum software.
Impact
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 products
| Vendor | Product | Affected versions |
|---|---|---|
| MyBB | MyBB Is Free And Open Source Forum Software. | before 1.8.40 |
Versions were read from the advisory text. No structured product data has been published for this record yet.