CVE-2026-45127 — MyBB: ACP Mass Mail draft resend CSRF
MyBB is free and open source forum software. Prior to 1.8.40, the ACP Mass Mail module does not validate certain requests correctly, allowing same-site attackers to create draft…
Published: 2026-08-18 · CVSS: 3.5 · CVSS 3.1
MyBB is free and open source forum software. Prior to 1.8.40, the ACP Mass Mail module does not validate certain requests correctly, allowing same-site attackers to create draft entries from archived entries by embedding a specially crafted URL. The Resend route in Admin CP, Users & Groups, Mass Mail, Mass Mailing Archive duplicates archived mailing entries into new drafts with mybb_massemails.status set to 0 on GET requests without request forgery protection. The uniquely identifying implementation details include Users & Groups → Mass Mail → Mass Mailing Archive, mybb_massemails.status = 0, and admin/modules/user/mass_mail.php. This issue is fixed in version 1.8.40.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7