CVE-2026-45121 MyBB: Insufficient permission check for calendar select

MyBB is free and open source forum software. Prior to 1.8.40, the calendar module does not check permissions consistently when listing calendars, allowing authenticated users to access titles of calendars that are otherwise inaccessible. The affected calendar-selection paths in calendar.php perfo...

CVE-2026-45121

In MyBB versions before 1.8.40, calendar.php performs permission checks against an invalid calendar context, allowing authenticated users to view titles of otherwise inaccessible calendars. CVSS 3.1 scores this MEDIUM (4.3) with network attack vector and low privileges required. Upgrade to versio...

EUVD-2026-61053

MyBB is free and open source forum software. Prior to 1.8.40, the calendar module does not check permissions consistently when listing calendars, allowing authenticated users to access titles of calendars that are otherwise inaccessible. The affected calendar-selection paths in calendar.php perfo...

EUVD-2026-61052

Impact The registration component does not validate the text-based Security Question CAPTCHA correctly, allowing attackers to bypass the challenge via a specially crafted value. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Details The public Registration workflow member.php?action=doregister...

CVE-2026-46482

Impact The registration component does not validate the text-based Security Question CAPTCHA correctly, allowing attackers to bypass the challenge via a specially crafted value. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Details The public Registration workflow member.php?action=doregister...

CVE-2026-46482 MyBB: Security Question insufficient validation

Impact The registration component does not validate the text-based Security Question CAPTCHA correctly, allowing attackers to bypass the challenge via a specially crafted value. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Details The public Registration workflow member.php?action=doregister...

CVE-2026-46482

MyBB's registration flow (member.php?action=do_register) accepts a hidden question_id field and validates the Security Question answer without a fail-closed fallback. A blank, forged, or expired question_id lets the request proceed, enabling CAPTCHA bypass for automated account creation. CVSS 3.1...

CVE-2026-45123

MyBB is free and open source forum software. Prior to 1.8.40, the remote requests feature does not correctly handle IPv6 addresses, resulting in a server-side request forgery vulnerability. The default disallowed remote hosts list does not include IPv6 addresses. Verification in fetchremotefile...

CVE-2026-45123

MyBB (open-source forum software) versions prior to 1.8.40 are affected by a server-side request forgery (SSRF) vulnerability in the remote requests feature. The root cause is a fail-open verification in fetch_remote_file() within inc/functions.php: the function get_ip_by_hostname() does not retu...

EUVD-2026-61051

MyBB is free and open source forum software. Prior to 1.8.40, the remote requests feature does not correctly handle IPv6 addresses, resulting in a server-side request forgery vulnerability. The default disallowed remote hosts list does not include IPv6 addresses. Verification in fetchremotefile...

CVE-2026-45123 MyBB: IPv6 SSRF

MyBB is free and open source forum software. Prior to 1.8.40, the remote requests feature does not correctly handle IPv6 addresses, resulting in a server-side request forgery vulnerability. The default disallowed remote hosts list does not include IPv6 addresses. Verification in fetchremotefile...

CVE-2026-45128

MyBB is free and open source forum software. Prior to 1.8.40, the ACP Users View Manager module does not validate requests correctly, allowing same-site attackers to change a victim administrator's default user list view by embedding a specially crafted URL. The Set as Default control named...

CVE-2026-45128 MyBB: ACP Users View Manager default CSRF

MyBB is free and open source forum software. Prior to 1.8.40, the ACP Users View Manager module does not validate requests correctly, allowing same-site attackers to change a victim administrator's default user list view by embedding a specially crafted URL. The Set as Default control named...

CVE-2026-45128

MyBB (open-source forum software) versions prior to 1.8.40 are affected by a CSRF vulnerability in the ACP Users View Manager module. The set_default control in Admin CP → Users & Groups → Users → View Manager processes state-changing actions on GET requests without request forgery protection, im...

EUVD-2026-61050

MyBB is free and open source forum software. Prior to 1.8.40, the ACP Users View Manager module does not validate requests correctly, allowing same-site attackers to change a victim administrator's default user list view by embedding a specially crafted URL. The Set as Default control named...

CVE-2026-45127

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...

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 entries from archived entries by embedding a specially crafted URL. The Resend route in Admin CP, Users & Groups, Mass...

CVE-2026-45127

MyBB versions prior to 1.8.40 have a CSRF flaw in the ACP Mass Mail Resend route: the admin/modules/user/mass_mail.php endpoint duplicates archived entries into new drafts (setting mybb_massemails.status = 0) on unprotected GET requests. A same-site attacker can trigger this via a crafted URL. Up...

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 entries from archived entries by embedding a specially crafted URL. The Resend route in Admin CP, Users & Groups, Mass...

EUVD-2026-60977

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...