CVE-2026-45117

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.

• CWE-94

• https://github.com/mybb/mybb/commit/0fe713e3b964bfc878ea65bdd9f746f585f6ebbf
• https://github.com/mybb/mybb/releases/tag/mybb_1840
• https://github.com/mybb/mybb/security/advisories/GHSA-gpc4-77rp-3xqr
• https://mybb.com/versions/1.8.40

Published

Aug 18, 2026

Last Modified

Sep 8, 2026

Status

Deferred

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-45108Himmelblau is an interoperability suite for Microsoft Azure …8.4
• CVE-2026-45109Next.js is a React framework for building full-stack web app…7.5
• CVE-2026-4511A security vulnerability has been detected in vanna-ai vanna…6.3
• CVE-2026-45112Allocation of Resources Without Limits or Throttling vulnera…7.5
• CVE-2026-45115MyBB is free and open source forum software. Prior to 1.8.40…8.7
• CVE-2026-45116MyBB is free and open source forum software. Prior to 1.8.40…8.7
• CVE-2026-45118MyBB is free and open source forum software. Prior to 1.8.40…9.3
• CVE-2026-45119MyBB is free and open source forum software. Prior to 1.8.40…4.6
• CVE-2026-4512The reCaptcha by WebDesignBy WordPress plugin before 2.0 doe…3.5
• CVE-2026-45120MyBB is free and open source forum software. Prior to 1.8.40…5.4
• CVE-2026-45121MyBB is free and open source forum software. Prior to 1.8.40…4.3
• CVE-2026-45122MyBB is free and open source forum software. Prior to 1.8.40…4.3