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CVE-2026-45117

MyBB: Installer database configuration RCE

Published: Aug 18, 2026Updated: Aug 18, 2026 Sources: CVE List NVDCWE-94
9.8CRITICAL
NVD MITRE
EPSS Score
0.8%
Top 46.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-94

Affected Products

mybb
oss-projectaka mybb forums
mybb
Web & CMS Plugins

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://github.com/mybb/mybb/security/advisories/GHSA-gpc4-77rp-3xqr
github.com
https://github.com/mybb/mybb/commit/0fe713e3b964bfc878ea65bdd9f746f585f6ebbf
github.com
https://github.com/mybb/mybb/releases/tag/mybb_1840
github.com
and 1 more references View all →

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