CVE-2026-45117

Published: Aug 18, 2026Modified: Sep 8, 2026Deferred

9.8

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitability: 3.9 / Impact: 5.9

Source: security-advisories@github.com (Secondary)

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.

Related CWEs

CWE-94

Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

References (4)

https://github.com/mybb/mybb/commit/0fe713e3b964bfc878ea65bdd9f746f585f6ebbf

Source: security-advisories@github.com

https://github.com/mybb/mybb/releases/tag/mybb_1840

Source: security-advisories@github.com

https://github.com/mybb/mybb/security/advisories/GHSA-gpc4-77rp-3xqr

Source: security-advisories@github.com

https://mybb.com/versions/1.8.40

Source: security-advisories@github.com

Timeline

No history available yet.