CVE-2026-45127MyBB: ACP Mass Mail draft resend CSRF
Updated under an hour ago ()
Does this affect you?
It affects mybb. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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.
- CVSS
- 3.5 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
- Weakness (CWE)
- CWE-352
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Aug 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
mybb mybb mybb:mybb (from the name) | before 1.8.40 | CNA record |
References
- https://github.com/mybb/mybb/security/advisories/GHSA-xx78-g79m-qvgqx-refsource-confirm
- https://github.com/mybb/mybb/commit/a95c5d6730b943adab7e54bc209c051f98843a3bx-refsource-misc
- https://github.com/mybb/mybb/releases/tag/mybb_1840x-refsource-misc
- https://mybb.com/versions/1.8.40x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.