Description
MyBB is free and open source forum software. From 1.8.13 until 1.8.40, the installer module does not properly escape user-supplied database configuration values written to the configuration file, resulting in PHP code injection and remote code execution when the installer is available. install/index.php processes the values with addcslashes(), but the $characters argument added in MyBB 1.8.13 does not include the backslash character, allowing crafted input to escape the generated PHP string. The uniquely identifying implementation details include introduced in MyBB 1.8.13. This issue is fixed in version 1.8.40.
Published: 2026-08-18
Score: 9.8 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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History

Tue, 18 Aug 2026 17:45:00 +0000

Type Values Removed Values Added
First Time appeared Mybb
Mybb mybb
Vendors & Products Mybb
Mybb mybb

Tue, 18 Aug 2026 16:00:00 +0000

Type Values Removed Values Added
Description MyBB is free and open source forum software. From 1.8.13 until 1.8.40, the installer module does not properly escape user-supplied database configuration values written to the configuration file, resulting in PHP code injection and remote code execution when the installer is available. install/index.php processes the values with addcslashes(), but the $characters argument added in MyBB 1.8.13 does not include the backslash character, allowing crafted input to escape the generated PHP string. The uniquely identifying implementation details include introduced in MyBB 1.8.13. This issue is fixed in version 1.8.40.
Title MyBB: Installer database configuration RCE
Weaknesses CWE-94
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-18T15:53:29.914Z

Reserved: 2026-05-08T20:08:17.207Z

Link: CVE-2026-45117

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-18T16:17:06.493

Modified: 2026-08-18T16:17:06.493

Link: CVE-2026-45117

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T17:30:15Z

Weaknesses