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 set_default in Admin CP, Users & Groups, Users, View Manager changes the administrator's default view on GET requests without request forgery protection. The uniquely identifying implementation details include Users & Groups → Users → View Manager, and admin/inc/functions_view_manager.php. This issue is fixed in version 1.8.40.

CVSS v3 3.5 LOW

3.5^/10

CVSS v3 : LOW

Vector :

Exploitability : 2.1 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/mybb/mybb/commit/736a2bcbc7cc104df8ae6c0a160aa3917a1ceec0
https://github.com/mybb/mybb/releases/tag/mybb_1840
https://github.com/mybb/mybb/security/advisories/GHSA-m6hr-25cj-p58q
https://mybb.com/versions/1.8.40

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-18 16:17

Updated : 2026-09-08 21:02

NVD link : CVE-2026-45128

Mitre link : CVE-2026-45128

CVE.ORG link : CVE-2026-45128

JSON object : View

Products Affected

No product.

CWE

CWE-352

Cross-Site Request Forgery (CSRF)

{"id": "CVE-2026-45128", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-45128", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-18T17:55:42.819787Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 3.5, "attackVector": "NETWORK", "baseSeverity": "LOW", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 2.1}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "mybb", "product": "mybb", "versions": [{"status": "affected", "version": "< 1.8.40"}]}]}], "published": "2026-08-18T16:17:08.087", "references": [{"url": "https://github.com/mybb/mybb/commit/736a2bcbc7cc104df8ae6c0a160aa3917a1ceec0", "source": "security-advisories@github.com"}, {"url": "https://github.com/mybb/mybb/releases/tag/mybb_1840", "source": "security-advisories@github.com"}, {"url": "https://github.com/mybb/mybb/security/advisories/GHSA-m6hr-25cj-p58q", "source": "security-advisories@github.com"}, {"url": "https://mybb.com/versions/1.8.40", "source": "security-advisories@github.com"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-352"}]}], "descriptions": [{"lang": "en", "value": "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 set_default in Admin CP, Users & Groups, Users, View Manager changes the administrator's default view on GET requests without request forgery protection. The uniquely identifying implementation details include Users & Groups \u2192 Users \u2192 View Manager, and admin/inc/functions_view_manager.php. This issue is fixed in version 1.8.40."}], "lastModified": "2026-09-08T21:02:26.047", "sourceIdentifier": "security-advisories@github.com"}