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CVE-2026-45127 Details

UNDERGOING ENRICHMENT

The CVE is currently being enriched by the Volerion team. The enrichment process results in the association of reference link tags, CVSS, and CPE applicability statement data.

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.

Metrics

CVSS 3.x Severity and Vector Strings:

VolerionCVSS-B:…Vector:This vulnerability is currently being analyzed.

CNA: [email protected]CVSS-B:3.5 LOWVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.

URL	Source(s)	Tag(s)
https://github.com/mybb/mybb/commit/a95c5d6730b943adab7e54bc209c051f98843a3b	[email protected]
https://github.com/mybb/mybb/releases/tag/mybb_1840	[email protected]
https://github.com/mybb/mybb/security/advisories/GHSA-xx78-g79m-qvgq	[email protected]
https://mybb.com/versions/1.8.40	[email protected]

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-352	Cross-Site Request Forgery (CSRF)	[email protected]

Affected Products

This vulnerability is currently being analyzed

Change History

2 change records found show changes

Date	Action	Recorded By
Aug 19, 2026	CVE Modified	CISA-ADP
Aug 18, 2026	New CVE Received	[email protected]