CVE-2026-45127
MyBB: ACP Mass Mail draft resend CSRF
- State
- Published
- Severity
- 3.5 Low
- Published
- Aug 18, 2026
- Updated
- Aug 19, 2026
- Reserved
- May 8, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 3.5 Low | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N | GitHub_M |
Weaknesses
- CWE-352 Cross-Site Request Forgery (CSRF)
Affected Products
| Product | Versions |
|---|---|
mybbmybb |
|
References
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