Cloudanix VulnDB

CVE-2026-45125

Medium · 5.3

CVSS

5.3

EPSS

0.4%

Published

Aug 18, 2026

CISA due date

—

The record

MyBB is free and open source forum software. Prior to 1.8.40, the Email User controller does not sanitize sender names correctly, resulting in mail header injection. member.php?action=do_emailuser accepts the fromname HTTP parameter for guests or the stored username for authenticated users when the cansendemail group permission is enabled. When mail_handler is set to the default PHP mail value, the sender name is used without sanitization in Return-Path and Reply-To headers, allowing arbitrary headers to be injected with CRLF sequences. This issue is fixed in version 1.8.40.

Affected packages

Ecosystem Package Introduced Fixed

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